Add functional predicate XNOR (#181)

Add new function, Xnor, designed to create a composed predicate representing
the logical Exclusive NOR (XNOR) operation applied to a list of predicates.
The XNOR operation is a logical operation that returns true only
if all operands have the same boolean value

.github/workflows/codecov.yml

@@ -3,11 +3,9 @@ on:
   push:
     branches:
       - main
-      # - v2
   pull_request:
     branches:
       - main
-      # - v2
 jobs:
   build:
     runs-on: ubuntu-latest
@@ -17,8 +15,10 @@ jobs:
           fetch-depth: 2
       - uses: actions/setup-go@v2
         with:
-          go-version: "1.18"
+          go-version: "1.20"
       - name: Run coverage
         run: go test -v ./... -coverprofile=coverage.txt -covermode=atomic
+      - name: Run govet
+        run: go vet -v ./...
       - name: Upload coverage to Codecov
         run: bash <(curl -s https://codecov.io/bash)

README.md

@@ -608,6 +608,7 @@ import set "github.com/duke-git/lancet/v2/datastructure/set"
 import tree "github.com/duke-git/lancet/v2/datastructure/tree"
 import heap "github.com/duke-git/lancet/v2/datastructure/heap"
 import hashmap "github.com/duke-git/lancet/v2/datastructure/hashmap"
+import optional "github.com/duke-git/lancet/v2/datastructure/optional"
 ```
 
 #### Structure list:
@@ -630,6 +631,9 @@ import hashmap "github.com/duke-git/lancet/v2/datastructure/hashmap"
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/datastructure/heap.md)]
 -   **<big>Hashmap</big>** : hash map structure.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/datastructure/hashmap.md)]
+-   **<big>Optional</big>** : Optional container.
+    [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/datastructure/optional.md)]
+      
 
 <h3 id="fileutil"> 9. Fileutil package implements some basic functions for file operations. &nbsp; &nbsp; &nbsp; &nbsp;<a href="#index">index</a></h3>
 
@@ -708,7 +712,7 @@ import "github.com/duke-git/lancet/v2/fileutil"
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/fileutil.md#WriteCsvFile)]
 -   **<big>WriteMapsToCsv</big>** : write slice of map to csv file.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/fileutil.md#WriteMapsToCsv)]
-    [[play](https://go.dev/play/p/dAXm58Q5U1o)]
+    [[play](https://go.dev/play/p/umAIomZFV1c)]
 -   **<big>WriteBytesToFile</big>** : write bytes to target file.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/fileutil.md#WriteBytesToFile)]
     [[play](https://go.dev/play/p/s7QlDxMj3P8)]
@@ -1182,8 +1186,10 @@ import "github.com/duke-git/lancet/v2/slice"
     [[play](https://go.dev/play/p/v2U2deugKuV)]
 -   **<big>DeleteAt</big>** : delete the element of slice at index.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/slice.md#DeleteAt)]
+    [[play](https://go.dev/play/p/800B1dPBYyd)]
 -   **<big>DeleteRange</big>** : delete the element of slice from start index to end index（exclude).
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/slice.md#DeleteRange)]
+    [[play](https://go.dev/play/p/945HwiNrnle)]
 -   **<big>Drop</big>** : drop n elements from the start of a slice.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/en/api/packages/slice.md#Drop)]
     [[play](https://go.dev/play/p/jnPO2yQsT8H)]

README_zh-CN.md

@@ -709,7 +709,7 @@ import "github.com/duke-git/lancet/v2/fileutil"
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/api/packages/fileutil.md#WriteCsvFile)]
 -   **<big>WriteMapsToCsv</big>** : 将map切片写入csv文件中。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/api/packages/fileutil.md#WriteMapsToCsv)]
-    [[play](https://go.dev/play/p/dAXm58Q5U1o)]
+    [[play](https://go.dev/play/p/umAIomZFV1c)]
 -   **<big>WriteBytesToFile</big>** : 将 bytes 写入文件。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/api/packages/fileutil.md#WriteBytesToFile)]
     [[play](https://go.dev/play/p/s7QlDxMj3P8)]
@@ -1181,8 +1181,10 @@ import "github.com/duke-git/lancet/v2/slice"
     [[play](https://go.dev/play/p/v2U2deugKuV)]
 -   **<big>DeleteAt</big>** : 删除切片中指定索引到的元素。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/api/packages/slice.md#DeleteAt)]
+    [[play](https://go.dev/play/p/800B1dPBYyd)]
 -   **<big>DeleteRange</big>** : 删除切片中指定开始索引到结束索引的元素。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/api/packages/slice.md#DeleteRange)]
+    [[play](https://go.dev/play/p/945HwiNrnle)]
 -   **<big>Drop</big>** : 从切片头部删除 n 个元素。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/api/packages/slice.md#Drop)]
     [[play](https://go.dev/play/p/jnPO2yQsT8H)]

compare/compare_test.go

@@ -1,6 +1,7 @@
 package compare
 
 import (
+	"encoding/json"
 	"testing"
 	"time"
 
@@ -11,6 +12,7 @@ func TestEqual(t *testing.T) {
 	t.Parallel()
 	assert := internal.NewAssert(t, "TestEqual")
 
+	// basic type
 	assert.Equal(true, Equal(1, 1))
 	assert.Equal(true, Equal(int64(1), int64(1)))
 	assert.Equal(true, Equal("a", "a"))
@@ -25,6 +27,7 @@ func TestEqual(t *testing.T) {
 	assert.Equal(false, Equal([]int{1, 2}, []int{1, 2, 3}))
 	assert.Equal(false, Equal(map[int]string{1: "a", 2: "b"}, map[int]string{1: "a"}))
 
+	// time
 	time1 := time.Now()
 	time2 := time1.Add(time.Second)
 	time3 := time1.Add(time.Second)
@@ -32,6 +35,7 @@ func TestEqual(t *testing.T) {
 	assert.Equal(false, Equal(time1, time2))
 	assert.Equal(true, Equal(time2, time3))
 
+	// struct
 	st1 := struct {
 		A string
 		B string
@@ -58,6 +62,19 @@ func TestEqual(t *testing.T) {
 
 	assert.Equal(true, Equal(st1, st2))
 	assert.Equal(false, Equal(st1, st3))
+
+	//byte slice
+	bs1 := []byte("hello")
+	bs2 := []byte("hello")
+	assert.Equal(true, Equal(bs1, bs2))
+
+	// json.Number
+	var jsonNumber1, jsonNumber2 json.Number
+	json.Unmarshal([]byte(`123`), &jsonNumber1)
+	json.Unmarshal([]byte(`123`), &jsonNumber2)
+
+	assert.Equal(true, Equal(jsonNumber1, jsonNumber2))
+
 }
 
 func TestEqualValue(t *testing.T) {
@@ -69,6 +86,13 @@ func TestEqualValue(t *testing.T) {
 	assert.Equal(true, EqualValue(1, "1"))
 
 	assert.Equal(false, EqualValue(1, "2"))
+
+	// json.Number
+	var jsonNumber1, jsonNumber2 json.Number
+	json.Unmarshal([]byte(`123`), &jsonNumber1)
+	json.Unmarshal([]byte(`123`), &jsonNumber2)
+
+	assert.Equal(true, EqualValue(jsonNumber1, 123))
 }
 
 func TestLessThan(t *testing.T) {
@@ -85,6 +109,17 @@ func TestLessThan(t *testing.T) {
 
 	assert.Equal(false, LessThan(1, 1))
 	assert.Equal(false, LessThan(1, int64(1)))
+
+	bs1 := []byte("hello1")
+	bs2 := []byte("hello2")
+	assert.Equal(true, LessThan(bs1, bs2))
+
+	// json.Number
+	var jsonNumber1, jsonNumber2 json.Number
+	json.Unmarshal([]byte(`123`), &jsonNumber1)
+	json.Unmarshal([]byte(`124`), &jsonNumber2)
+
+	assert.Equal(true, LessThan(jsonNumber1, jsonNumber2))
 }
 
 func TestGreaterThan(t *testing.T) {
@@ -102,6 +137,17 @@ func TestGreaterThan(t *testing.T) {
 	assert.Equal(false, GreaterThan(1, 2))
 	assert.Equal(false, GreaterThan(int64(2), 1))
 	assert.Equal(false, GreaterThan("b", "c"))
+
+	bs1 := []byte("hello1")
+	bs2 := []byte("hello2")
+	assert.Equal(true, GreaterThan(bs2, bs1))
+
+	// json.Number
+	var jsonNumber1, jsonNumber2 json.Number
+	json.Unmarshal([]byte(`123`), &jsonNumber1)
+	json.Unmarshal([]byte(`124`), &jsonNumber2)
+
+	assert.Equal(true, GreaterThan(jsonNumber2, jsonNumber1))
 }
 
 func TestLessOrEqual(t *testing.T) {
@@ -119,6 +165,17 @@ func TestLessOrEqual(t *testing.T) {
 
 	assert.Equal(false, LessOrEqual(2, 1))
 	assert.Equal(false, LessOrEqual(1, int64(2)))
+
+	bs1 := []byte("hello1")
+	bs2 := []byte("hello2")
+	assert.Equal(true, LessOrEqual(bs1, bs2))
+
+	// json.Number
+	var jsonNumber1, jsonNumber2 json.Number
+	json.Unmarshal([]byte(`123`), &jsonNumber1)
+	json.Unmarshal([]byte(`124`), &jsonNumber2)
+
+	assert.Equal(true, LessOrEqual(jsonNumber1, jsonNumber2))
 }
 
 func TestGreaterOrEqual(t *testing.T) {
@@ -137,6 +194,17 @@ func TestGreaterOrEqual(t *testing.T) {
 	assert.Equal(false, GreaterOrEqual(1, 2))
 	assert.Equal(false, GreaterOrEqual(int64(2), 1))
 	assert.Equal(false, GreaterOrEqual("b", "c"))
+
+	bs1 := []byte("hello1")
+	bs2 := []byte("hello2")
+	assert.Equal(true, GreaterOrEqual(bs2, bs1))
+
+	// json.Number
+	var jsonNumber1, jsonNumber2 json.Number
+	json.Unmarshal([]byte(`123`), &jsonNumber1)
+	json.Unmarshal([]byte(`124`), &jsonNumber2)
+
+	assert.Equal(true, GreaterOrEqual(jsonNumber2, jsonNumber1))
 }
 
 func TestInDelta(t *testing.T) {

datastructure/list/copyonwritelist.go

@@ -90,6 +90,35 @@ func lastIndexOf[T any](o T, e []T, start int, end int) int {
 	return -1
 }
 
+// LastIndexOfFunc returns the index of the last occurrence of the value in this list satisfying the
+// functional predicate f(T) bool
+// if not found return -1.
+func (l *CopyOnWriteList[T]) LastIndexOfFunc(f func(T) bool) int {
+	index := -1
+	data := l.getList()
+	for i := len(data) - 1; i >= 0; i-- {
+		if f(data[i]) {
+			index = i
+			break
+		}
+	}
+	return index
+}
+
+// IndexOfFunc returns the first index satisfying the functional predicate f(v) bool
+// if not found return -1.
+func (l *CopyOnWriteList[T]) IndexOfFunc(f func(T) bool) int {
+	index := -1
+	data := l.getList()
+	for i, v := range data {
+		if f(v) {
+			index = i
+			break
+		}
+	}
+	return index
+}
+
 // get returns the element at the specified position in this list.
 func get[T any](o []T, index int) *T {
 	return &o[index]

datastructure/list/copyonwritelist_test.go

@@ -1,8 +1,9 @@
 package datastructure
 
 import (
-	"github.com/duke-git/lancet/v2/internal"
 	"testing"
+
+	"github.com/duke-git/lancet/v2/internal"
 )
 
 func TestCopyOnWriteList_ValueOf(t *testing.T) {
@@ -233,3 +234,35 @@ func TestCopyOnWriteList_SubList(t *testing.T) {
 	subList = list.SubList(11, 1)
 	assert.Equal([]int{}, subList)
 }
+
+func TestCopyOnWriteListIndexOfFunc(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestIndexOfFunc")
+
+	list := NewCopyOnWriteList([]int{1, 2, 3})
+	i := list.IndexOfFunc(func(a int) bool { return a == 1 })
+	assert.Equal(0, i)
+
+	i = list.IndexOfFunc(func(a int) bool { return a == 4 })
+	assert.Equal(-1, i)
+}
+
+func TestNewCopyOnWriteListLastIndexOfFunc(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestLastIndexOfFunc")
+
+	list := NewCopyOnWriteList([]int{1, 2, 3, 3, 3, 3, 4, 5, 6, 9})
+	i := list.LastIndexOfFunc(func(a int) bool { return a == 3 })
+	assert.Equal(5, i)
+
+	i = list.LastIndexOfFunc(func(a int) bool { return a == 10 })
+	assert.Equal(-1, i)
+
+	i = list.LastIndexOfFunc(func(a int) bool { return a == 4 })
+	assert.Equal(6, i)
+
+	i = list.LastIndexOfFunc(func(a int) bool { return a == 1 })
+	assert.Equal(0, i)
+}

datastructure/optional/optional.go

@@ -0,0 +1,108 @@
+package optional
+
+import (
+	"sync"
+)
+
+// Optional is a type that may or may not contain a non-nil value.
+type Optional[T any] struct {
+	value *T
+	mu    *sync.RWMutex
+}
+
+// Default returns an default Optional instance.
+func Default[T any]() Optional[T] {
+	return Optional[T]{mu: &sync.RWMutex{}}
+}
+
+// Of returns an Optional with a non-nil value.
+func Of[T any](value T) Optional[T] {
+	return Optional[T]{value: &value, mu: &sync.RWMutex{}}
+}
+
+// FromNillable returns an Optional for a given value, which may be nil.
+func FromNillable[T any](value *T) Optional[T] {
+	if value == nil {
+		return Default[T]()
+	}
+	return Optional[T]{value: value, mu: &sync.RWMutex{}}
+}
+
+// IsNotNil checks if there is a value present.
+func (o Optional[T]) IsNotNil() bool {
+	o.mu.RLock()
+	defer o.mu.RUnlock()
+
+	return o.value != nil
+}
+
+// IsNil checks if the Optional is nil.
+func (o Optional[T]) IsNil() bool {
+	return !o.IsNotNil()
+}
+
+// IfNotNil performs the given action with the value if a value is not nil.
+func (o Optional[T]) IfNotNil(action func(value T)) {
+	o.mu.RLock()
+	defer o.mu.RUnlock()
+
+	if o.value != nil {
+		action(*o.value)
+	}
+}
+
+// IfNotNilOrElse performs the action with the value if present, otherwise performs the fallback action.
+func (o Optional[T]) IfNotNilOrElse(action func(value T), fallbackAction func()) {
+	o.mu.RLock()
+	defer o.mu.RUnlock()
+
+	if o.value != nil {
+		action(*o.value)
+	} else {
+		fallbackAction()
+	}
+}
+
+// Unwarp returns the value if not nil, otherwise panics.
+func (o Optional[T]) Unwarp() T {
+	o.mu.RLock()
+	defer o.mu.RUnlock()
+
+	if o.value == nil {
+		panic("Optional.Get: no value present")
+	}
+	return *o.value
+}
+
+// OrElse returns the value if is not nil, otherwise returns other.
+func (o Optional[T]) OrElse(other T) T {
+	o.mu.RLock()
+	defer o.mu.RUnlock()
+
+	if o.value != nil {
+		return *o.value
+	}
+	return other
+}
+
+// OrElseGet returns the value if is not nil, otherwise invokes action and returns the result.
+func (o Optional[T]) OrElseGet(action func() T) T {
+	o.mu.RLock()
+	defer o.mu.RUnlock()
+
+	if o.value != nil {
+		return *o.value
+	}
+	return action()
+}
+
+// OrElseTrigger returns the value if present, otherwise returns an error.
+func (o Optional[T]) OrElseTrigger(errorHandler func() error) (T, error) {
+	o.mu.RLock()
+	defer o.mu.RUnlock()
+
+	if o.value == nil {
+		return *new(T), errorHandler()
+	}
+	return *o.value, nil
+}

datastructure/optional/optional_test.go

@@ -0,0 +1,151 @@
+package optional
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/duke-git/lancet/v2/internal"
+)
+
+func TestDefault(t *testing.T) {
+	assert := internal.NewAssert(t, "TestEmpty")
+	opt := Default[int]()
+
+	assert.ShouldBeTrue(opt.IsNil())
+}
+
+func TestOf(t *testing.T) {
+	assert := internal.NewAssert(t, "TestOf")
+	value := 42
+	opt := Of(value)
+
+	assert.ShouldBeTrue(opt.IsNotNil())
+	assert.Equal(opt.Unwarp(), value)
+}
+
+func TestFromNillable(t *testing.T) {
+	assert := internal.NewAssert(t, "TestOfNullable")
+	var value *int = nil
+	opt := FromNillable(value)
+
+	assert.ShouldBeFalse(opt.IsNotNil())
+
+	value = new(int)
+	*value = 42
+	opt = FromNillable(value)
+
+	assert.ShouldBeTrue(opt.IsNotNil())
+}
+
+func TestOrElse(t *testing.T) {
+	assert := internal.NewAssert(t, "TestOrElse")
+	optDefault := Default[int]()
+	defaultValue := 100
+
+	val := optDefault.OrElse(defaultValue)
+	assert.Equal(val, defaultValue)
+
+	optWithValue := Of(42)
+	val = optWithValue.OrElse(defaultValue)
+	assert.Equal(val, 42)
+}
+
+func TestOrElseGetHappyPath(t *testing.T) {
+	assert := internal.NewAssert(t, "TestOrElseGetHappyPath")
+	optWithValue := Of(42)
+	action := func() int { return 100 }
+
+	val := optWithValue.OrElseGet(action)
+	assert.Equal(val, 42)
+}
+
+func TestOrElseGet(t *testing.T) {
+	assert := internal.NewAssert(t, "TestOrElseGet")
+	optDefault := Default[int]()
+	action := func() int { return 100 }
+
+	val := optDefault.OrElseGet(action)
+	assert.Equal(val, action())
+}
+
+func TestOrElseTrigger(t *testing.T) {
+	assert := internal.NewAssert(t, "OrElseTrigger")
+	optDefault := Default[int]()
+	_, err := optDefault.OrElseTrigger(func() error { return errors.New("no value") })
+
+	assert.Equal(err.Error(), "no value")
+
+	optWithValue := Of(42)
+	val, err := optWithValue.OrElseTrigger(func() error { return errors.New("no value") })
+
+	assert.IsNil(err)
+	assert.Equal(val, 42)
+}
+
+func TestIfNotNil(t *testing.T) {
+	assert := internal.NewAssert(t, "IfNotNil")
+	called := false
+	action := func(value int) { called = true }
+
+	optDefault := Default[int]()
+	optDefault.IfNotNil(action)
+
+	assert.ShouldBeFalse(called)
+
+	called = false // Reset for next test
+	optWithValue := Of(42)
+	optWithValue.IfNotNil(action)
+
+	assert.ShouldBeTrue(called)
+}
+
+func TestIfNotNilOrElse(t *testing.T) {
+	assert := internal.NewAssert(t, "TestIfNotNilOrElse")
+
+	// Test when value is present
+	calledWithValue := false
+	valueAction := func(value int) { calledWithValue = true }
+	fallbackAction := func() { t.Errorf("Empty action should not be called when value is present") }
+
+	optWithValue := Of(42)
+	optWithValue.IfNotNilOrElse(valueAction, fallbackAction)
+
+	assert.ShouldBeTrue(calledWithValue)
+
+	// Test when value is not present
+	calledWithEmpty := false
+	valueAction = func(value int) { t.Errorf("Value action should not be called when value is not present") }
+	fallbackAction = func() { calledWithEmpty = true }
+
+	optDefault := Default[int]()
+	optDefault.IfNotNilOrElse(valueAction, fallbackAction)
+
+	assert.ShouldBeTrue(calledWithEmpty)
+}
+
+func TestGetWithPanicStandard(t *testing.T) {
+	assert := internal.NewAssert(t, "TestGetWithPanicStandard")
+
+	// Test when value is present
+	optWithValue := Of(42)
+	func() {
+		defer func() {
+			r := recover()
+			assert.IsNil(r)
+		}()
+		val := optWithValue.Unwarp()
+		if val != 42 {
+			t.Errorf("Expected Unwarp to return 42, got %v", val)
+		}
+	}()
+
+	// Test when value is not present
+	optDefault := Default[int]()
+	func() {
+		defer func() {
+			r := recover()
+			assert.IsNotNil(r)
+		}()
+		_ = optDefault.Unwarp()
+	}()
+}

datastructure/set/set.go

@@ -7,15 +7,15 @@ package datastructure
 // Set is a data container, like slice, but element of set is not duplicate.
 type Set[T comparable] map[T]struct{}
 
-// NewSet return a instance of set
-func NewSet[T comparable](items ...T) Set[T] {
+// New create a instance of set from given values.
+func New[T comparable](items ...T) Set[T] {
 	set := make(Set[T])
 	set.Add(items...)
 	return set
 }
 
-// NewSetFromSlice create a set from slice
-func NewSetFromSlice[T comparable](items []T) Set[T] {
+// FromSlice create a set from given slice.
+func FromSlice[T comparable](items []T) Set[T] {
 	set := make(Set[T])
 	for _, item := range items {
 		set.Add(item)
@@ -77,7 +77,7 @@ func (s Set[T]) ContainAll(other Set[T]) bool {
 
 // Clone return a copy of set
 func (s Set[T]) Clone() Set[T] {
-	set := NewSet[T]()
+	set := New[T]()
 	set.Add(s.Values()...)
 	return set
 }
@@ -135,7 +135,7 @@ func (s Set[T]) Union(other Set[T]) Set[T] {
 
 // Intersection creates a new set whose element both be contained in set s and other
 func (s Set[T]) Intersection(other Set[T]) Set[T] {
-	set := NewSet[T]()
+	set := New[T]()
 	s.Iterate(func(value T) {
 		if other.Contain(value) {
 			set.Add(value)
@@ -147,7 +147,7 @@ func (s Set[T]) Intersection(other Set[T]) Set[T] {
 
 // SymmetricDifference creates a new set whose element is in set1 or set2, but not in both sets
 func (s Set[T]) SymmetricDifference(other Set[T]) Set[T] {
-	set := NewSet[T]()
+	set := New[T]()
 	s.Iterate(func(value T) {
 		if !other.Contain(value) {
 			set.Add(value)
@@ -165,7 +165,7 @@ func (s Set[T]) SymmetricDifference(other Set[T]) Set[T] {
 
 // Minus creates an set of whose element in origin set but not in compared set
 func (s Set[T]) Minus(comparedSet Set[T]) Set[T] {
-	set := NewSet[T]()
+	set := New[T]()
 
 	s.Iterate(func(value T) {
 		if !comparedSet.Contain(value) {

datastructure/set/set_test.go

@@ -6,18 +6,18 @@ import (
 	"github.com/duke-git/lancet/v2/internal"
 )
 
-func TestSet_NewSetFromSlice(t *testing.T) {
+func TestSet_FromSlice(t *testing.T) {
 	t.Parallel()
 
-	assert := internal.NewAssert(t, "TestSet_NewSetFromSlice")
+	assert := internal.NewAssert(t, "TestSet_FromSlice")
 
-	s1 := NewSetFromSlice([]int{1, 2, 2, 3})
+	s1 := FromSlice([]int{1, 2, 2, 3})
 	assert.Equal(3, s1.Size())
 	assert.Equal(true, s1.Contain(1))
 	assert.Equal(true, s1.Contain(2))
 	assert.Equal(true, s1.Contain(3))
 
-	s2 := NewSetFromSlice([]int{})
+	s2 := FromSlice([]int{})
 	assert.Equal(0, s2.Size())
 }
 
@@ -26,10 +26,10 @@ func TestSet_Add(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_Add")
 
-	set := NewSet[int]()
+	set := New[int]()
 	set.Add(1, 2, 3)
 
-	cmpSet := NewSet(1, 2, 3)
+	cmpSet := New(1, 2, 3)
 
 	assert.Equal(true, set.Equal(cmpSet))
 }
@@ -39,12 +39,12 @@ func TestSet_AddIfNotExist(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_AddIfNotExist")
 
-	set := NewSet[int]()
+	set := New[int]()
 	set.Add(1, 2, 3)
 
 	assert.Equal(false, set.AddIfNotExist(1))
 	assert.Equal(true, set.AddIfNotExist(4))
-	assert.Equal(NewSet(1, 2, 3, 4), set)
+	assert.Equal(New(1, 2, 3, 4), set)
 }
 
 func TestSet_AddIfNotExistBy(t *testing.T) {
@@ -52,7 +52,7 @@ func TestSet_AddIfNotExistBy(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_AddIfNotExistBy")
 
-	set := NewSet[int]()
+	set := New[int]()
 	set.Add(1, 2)
 
 	ok := set.AddIfNotExistBy(3, func(val int) bool {
@@ -75,7 +75,7 @@ func TestSet_Contain(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_Contain")
 
-	set := NewSet[int]()
+	set := New[int]()
 	set.Add(1, 2, 3)
 
 	assert.Equal(true, set.Contain(1))
@@ -87,9 +87,9 @@ func TestSet_ContainAll(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_ContainAll")
 
-	set1 := NewSet(1, 2, 3)
-	set2 := NewSet(1, 2)
-	set3 := NewSet(1, 2, 3, 4)
+	set1 := New(1, 2, 3)
+	set2 := New(1, 2)
+	set3 := New(1, 2, 3, 4)
 
 	assert.Equal(true, set1.ContainAll(set2))
 	assert.Equal(false, set1.ContainAll(set3))
@@ -100,7 +100,7 @@ func TestSet_Clone(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_Clone")
 
-	set1 := NewSet(1, 2, 3)
+	set1 := New(1, 2, 3)
 	set2 := set1.Clone()
 
 	assert.Equal(true, set1.Size() == set2.Size())
@@ -112,11 +112,11 @@ func TestSet_Delete(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_Delete")
 
-	set := NewSet[int]()
+	set := New[int]()
 	set.Add(1, 2, 3)
 	set.Delete(3)
 
-	assert.Equal(true, set.Equal(NewSet(1, 2)))
+	assert.Equal(true, set.Equal(New(1, 2)))
 }
 
 func TestSet_Equal(t *testing.T) {
@@ -124,9 +124,9 @@ func TestSet_Equal(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_Equal")
 
-	set1 := NewSet(1, 2, 3)
-	set2 := NewSet(1, 2, 3)
-	set3 := NewSet(1, 2, 3, 4)
+	set1 := New(1, 2, 3)
+	set2 := New(1, 2, 3)
+	set3 := New(1, 2, 3, 4)
 
 	assert.Equal(true, set1.Equal(set2))
 	assert.Equal(false, set1.Equal(set3))
@@ -137,7 +137,7 @@ func TestSet_Iterate(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_Iterate")
 
-	set := NewSet(1, 2, 3)
+	set := New(1, 2, 3)
 	arr := []int{}
 	set.Iterate(func(value int) {
 		arr = append(arr, value)
@@ -151,7 +151,7 @@ func TestSet_IsEmpty(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_IsEmpty")
 
-	set := NewSet[int]()
+	set := New[int]()
 	assert.Equal(true, set.IsEmpty())
 }
 
@@ -160,7 +160,7 @@ func TestSet_Size(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_Size")
 
-	set := NewSet(1, 2, 3)
+	set := New(1, 2, 3)
 	assert.Equal(3, set.Size())
 }
 
@@ -169,7 +169,7 @@ func TestSet_Values(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_Values")
 
-	set := NewSet(1, 2, 3)
+	set := New(1, 2, 3)
 	values := set.Values()
 
 	assert.Equal(3, len(values))
@@ -180,12 +180,12 @@ func TestSet_Union(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_Union")
 
-	set1 := NewSet(1, 2, 3)
-	set2 := NewSet(2, 3, 4, 5)
+	set1 := New(1, 2, 3)
+	set2 := New(2, 3, 4, 5)
 
 	unionSet := set1.Union(set2)
 
-	assert.Equal(NewSet(1, 2, 3, 4, 5), unionSet)
+	assert.Equal(New(1, 2, 3, 4, 5), unionSet)
 }
 
 func TestSet_Intersection(t *testing.T) {
@@ -193,11 +193,11 @@ func TestSet_Intersection(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_Intersection")
 
-	set1 := NewSet(1, 2, 3)
-	set2 := NewSet(2, 3, 4, 5)
+	set1 := New(1, 2, 3)
+	set2 := New(2, 3, 4, 5)
 	intersectionSet := set1.Intersection(set2)
 
-	assert.Equal(NewSet(2, 3), intersectionSet)
+	assert.Equal(New(2, 3), intersectionSet)
 }
 
 func TestSet_SymmetricDifference(t *testing.T) {
@@ -205,10 +205,10 @@ func TestSet_SymmetricDifference(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_SymmetricDifference")
 
-	set1 := NewSet(1, 2, 3)
-	set2 := NewSet(2, 3, 4, 5)
+	set1 := New(1, 2, 3)
+	set2 := New(2, 3, 4, 5)
 
-	assert.Equal(NewSet(1, 4, 5), set1.SymmetricDifference(set2))
+	assert.Equal(New(1, 4, 5), set1.SymmetricDifference(set2))
 }
 
 func TestSet_Minus(t *testing.T) {
@@ -216,16 +216,16 @@ func TestSet_Minus(t *testing.T) {
 
 	assert := internal.NewAssert(t, "TestSet_Minus")
 
-	set1 := NewSet(1, 2, 3)
-	set2 := NewSet(2, 3, 4, 5)
-	set3 := NewSet(2, 3)
+	set1 := New(1, 2, 3)
+	set2 := New(2, 3, 4, 5)
+	set3 := New(2, 3)
 
-	assert.Equal(NewSet(1), set1.Minus(set2))
-	assert.Equal(NewSet(4, 5), set2.Minus(set3))
+	assert.Equal(New(1), set1.Minus(set2))
+	assert.Equal(New(4, 5), set2.Minus(set3))
 }
 
 func TestEachWithBreak(t *testing.T) {
-	// s := NewSet(1, 2, 3, 4, 5)
+	// s := New(1, 2, 3, 4, 5)
 
 	// var sum int
 
@@ -244,7 +244,7 @@ func TestEachWithBreak(t *testing.T) {
 // func TestPop(t *testing.T) {
 // 	assert := internal.NewAssert(t, "TestPop")
 
-// 	s := NewSet[int]()
+// 	s := New[int]()
 
 // 	val, ok := s.Pop()
 // 	assert.Equal(0, val)
@@ -254,7 +254,7 @@ func TestEachWithBreak(t *testing.T) {
 // 	s.Add(2)
 // 	s.Add(3)
 
-// 	// s = NewSet(1, 2, 3, 4, 5)
+// 	// s = New(1, 2, 3, 4, 5)
 
 // 	val, ok = s.Pop()
 // 	assert.Equal(3, val)

docs/api/packages/datastructure/copyonwritelist.md

@@ -26,6 +26,8 @@ import (
 -   [Remove](#Remove)
 -   [IndexOf](#IndexOf)
 -   [LastIndexOf](#LastIndexOf)
+-   [IndexOfFunc](#IndexOfFunc)
+-   [LastIndexOfFunc](#LastIndexOfFunc)
 -   [IsEmpty](#IsEmpty)
 -   [Contain](#Contain)
 -   [ValueOf](#ValueOf)
@@ -198,6 +200,58 @@ func main()  {
 
 ```
 
+### <span id="IndexOfFunc">IndexOfFunc</span>
+<p>返回第一个满足判断函数f(v)的元素的索引，如果找不到则返回-1。</p>
+
+<b>函数签名:</b>
+
+```go
+func (l *CopyOnWriteList[T]) IndexOfFunc(f func(T) bool) int 
+```
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/list"
+)
+
+func main() {
+    l := list.NewCopyOnWriteList([]int{1, 2, 3})
+
+    fmt.Println(l.IndexOfFunc(func(a int) bool { return a == 1 })) //0
+    fmt.Println(l.IndexOfFunc(func(a int) bool { return a == 0 })) //-1
+}
+```
+
+### <span id="LastIndexOfFunc">LastIndexOfFunc</span>
+<p>返回最后一个满足判断函数f(v)的元素的索引，如果找不到则返回-1。</p>
+
+<b>函数签名:</b>
+
+```go
+func (l *CopyOnWriteList[T]) LastIndexOfFunc(f func(T) bool) int
+```
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/list"
+)
+
+func main() {
+    l := list.NewCopyOnWriteList([]int{1, 2, 3, 1})
+
+    fmt.Println(l.LastIndexOfFunc(func(a int) bool { return a == 1 })) // 3
+    fmt.Println(l.LastIndexOfFunc(func(a int) bool { return a == 0 })) //-1
+}
+```
+
 ### IsEmpty
 
 如果此列表不包含任何元素，则返回 true。

docs/api/packages/datastructure/optional.md

@@ -0,0 +1,412 @@
+# Optional
+Optional类型代表一个可选的值，它要么包含一个实际值，要么为空。
+
+<div STYLE="page-break-after: always;"></div>
+
+## 源码
+
+- [https://github.com/duke-git/lancet/blob/main/datastructure/optional/optional.go](https://github.com/duke-git/lancet/blob/main/datastructure/optional/optional.go)
+
+
+<div STYLE="page-break-after: always;"></div>
+
+## 用法
+```go
+import (
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+```
+
+<div STYLE="page-break-after: always;"></div>
+
+## 目录
+
+- [Of](#Of)
+- [FromNillable](#FromNillable)
+- [Default](#Default)
+- [IsNotNil](#IsNotNil)
+- [IsNil](#IsNil)
+- [IsNotNil](#IsNotNil)
+- [IfNotNilOrElse](#IfNotNilOrElse)
+- [Umwarp](#Umwarp)
+- [OrElse](#OrElse)
+- [OrElseGet](#OrElseGet)
+- [OrElseTrigger](#OrElseTrigger)
+
+
+<div STYLE="page-break-after: always;"></div>
+
+## 文档
+
+### <span id="Of">Of</span>
+<p>返回一个包含非空值的Optional。</p>
+
+<b>函数签名:</b>
+
+```go
+func Of[T any](value T) Optional[T]
+```
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    value := 42
+    opt := optional.Of(value)
+
+    fmt.Println(opt.Get())
+
+    // Output:
+    // 42
+}
+```
+
+### <span id="FromNillable">FromNillable</span>
+<p>返回一个包含给定值的Optional，该值可能为空 (nil)。</p>
+
+<b>函数签名:</b>
+
+```go
+func FromNillable[T any](value *T) Optional[T]
+```
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    var value *int = nil
+    opt := optional.FromNillable(value)
+
+    fmt.Println(opt.IsNotNil())
+
+    value = new(int)
+    *value = 42
+    opt = optional.FromNillable(value)
+
+    fmt.Println(opt.IsNotNil())
+
+
+    // Output:
+    // false
+    // true
+}
+```
+
+
+### <span id="Default">Default</span>
+<p>返回一个空Optional实例。</p>
+
+<b>函数签名:</b>
+
+```go
+func Default[T any]() Optional[T]
+```
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    optDefault := optional.Default[int]()
+    fmt.Println(optDefault.IsNil())
+
+    // Output:
+    // true
+}
+```
+
+
+### <span id="IsNil">IsNil</span>
+<p>验证Optional是否为空。</p>
+
+<b>函数签名:</b>
+
+```go
+func (o Optional[T]) IsNil() bool
+```
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    optDefault := optional.Default[int]()
+    fmt.Println(optDefault.IsNil())
+
+    // Output:
+    // true
+}
+```
+
+### <span id="IsNotNil">IsNotNil</span>
+<p>检查当前Optional内是否存在值。</p>
+
+<b>函数签名:</b>
+
+```go
+func (o Optional[T]) IsNotNil() bool
+```
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    var value *int = nil
+    opt := optional.FromNillable(value)
+
+    fmt.Println(opt.IsNotNil())
+
+    value = new(int)
+    *value = 42
+    opt = optional.FromNillable(value)
+
+    fmt.Println(opt.IsNotNil())
+
+
+    // Output:
+    // false
+    // true
+}
+```
+
+### <span id="IfNotNil">IfNotNil</span>
+<p>如果值存在，则使用action方法执行给定的操作。</p>
+
+<b>函数签名:</b>
+
+```go
+func (o Optional[T]) IfNotNil(action func(value T))
+```
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+     "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    called := false
+    action := func(value int) { called = true }
+
+    optDefault := optional.Default[int]()
+    optDefault.IfNotNil(action)
+
+    fmt.Println(called)
+
+    called = false // Reset for next test
+    optWithValue := optional.Of(42)
+    optWithValue.IfNotNil(action)
+
+    fmt.Println(optWithValue.IsNotNil())
+
+    // Output:
+    // false
+    // true
+}
+```
+
+
+### <span id="IfNotNilOrElse">IfNotNilOrElse</span>
+<p>根据是否存在值执行相应的操作：有值则执行指定操作，没有值则执行默认操作。</p>
+
+<b>函数签名:</b>
+
+```go
+func (o Optional[T]) IfNotNilOrElse(action func(value T), fallbackAction func())
+```
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    calledWithValue := false
+    valueAction := func(value int) { calledWithValue = true }
+    emptyAction := func() { t.Errorf("Empty action should not be called when value is present") }
+
+    optWithValue := optional.Of(42)
+    optWithValue.IfNotNilOrElse(valueAction, emptyAction)
+
+    fmt.Println(calledWithValue)
+
+    calledWithEmpty := false
+    valueAction = func(value int) { t.Errorf("Value action should not be called when value is not present") }
+    emptyAction = func() { calledWithEmpty = true }
+
+    optDefault := optional.Default[int]()
+    optDefault.IfNotNilOrElse(valueAction, emptyAction)
+
+    fmt.Println(calledWithEmpty)
+
+    // Output:
+    // true
+    // true
+}
+```
+
+### <span id="Unwrap">Unwrap</span>
+<p>如果存在，返回该值，否则引发panic。</p>
+
+<b>函数签名:</b>
+
+```go
+func (o Optional[T]) Unwrap() T
+```
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    value := 42
+    opt := optional.Of(value)
+
+    fmt.Println(opt.Unwrap())
+
+    // Output:
+    // 42
+}
+```
+
+
+### <span id="OrElse">OrElse</span>
+<p>检查Optional值是否存在，如果存在，则直接返回该值。如果不存在，返回参数other值。</p>
+
+<b>函数签名:</b>
+
+```go
+func (o Optional[T]) OrElse(other T) T
+```
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    optDefault := optional.Empty[int]()
+    val := optDefault.OrElse(100)
+    fmt.Println(val)
+
+    optWithValue := optional.Of(42)
+    val = optWithValue.OrElse(100)
+    fmt.Println(val)
+
+    // Output:
+    // 100
+    // 42
+}
+```
+
+
+### <span id="OrElseGet">OrElseGet</span>
+<p>检查Optional值是否存在，如果存在，则直接返回该值。如果不存在，则调用一个提供的函数 (supplier)，并返回该函数的执行结果。</p>
+
+<b>函数签名:</b>
+
+```go
+func (o Optional[T]) OrElseGet(action func() T) T
+```
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    optDefault := optional.Default[int]()
+    action := func() int { return 100 }
+
+    val := optDefault.OrElseGet(action)
+    fmt.Println(val)
+
+    // Output:
+    // 100
+}
+```
+
+### <span id="OrElseTrigger">OrElseTrigger</span>
+<p>检查Optional值是否存在，如果存在，则直接返回该值，否则返回错误。</p>
+
+<b>函数签名:</b>
+
+```go
+ OrElseTrigger(errorHandler func() error) (T, error)
+```
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    optDefault := optional.Default[int]()
+    _, err := optDefault.OrElseTrigger(func() error { return errors.New("no value") })
+    
+    fmt.Println(err.Error())
+
+    optWithValue := optional.Of(42)
+    val, err := optWithValue.OrElseTrigger(func() error { return errors.New("no value") })
+
+    fmt.Println(val)
+    fmt.Println(err)
+
+    // Output:
+    // no value
+    // 42
+    // nil
+}
+```

docs/api/packages/datastructure/set.md

@@ -1,6 +1,6 @@
 # Set
 
-Set 集合数据结构，类似列表。Set 中元素不重复。
+集合数据结构，类似列表。Set中元素不重复。
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -22,8 +22,8 @@ import (
 
 ## 目录
 
--   [NewSet](#NewSet)
--   [NewSetFromSlice](#NewSetFromSlice)
+-   [New](#New)
+-   [FromSlice](#FromSlice)
 -   [Values](#Values)
 -   [Add](#Add)
 -   [AddIfNotExist](#AddIfNotExist)
@@ -45,7 +45,7 @@ import (
 
 ## 文档
 
-### <span id="NewSet">NewSet</span>
+### <span id="New">New</span>
 
 <p>返回Set结构体对象</p>
 
@@ -53,7 +53,7 @@ import (
 
 ```go
 type Set[T comparable] map[T]bool
-func NewSet[T comparable](items ...T) Set[T]
+func New[T comparable](items ...T) Set[T]
 ```
 
 <b>示例:</b>
@@ -67,19 +67,19 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int](1,2,2,3)
+    st := set.New[int](1,2,2,3)
     fmt.Println(st.Values()) //1,2,3
 }
 ```
 
-### <span id="NewSetFromSlice">NewSetFromSlice</span>
+### <span id="FromSlice">FromSlice</span>
 
 <p>基于切片创建集合</p>
 
 <b>函数签名:</b>
 
 ```go
-func NewSetFromSlice[T comparable](items []T) Set[T]
+func FromSlice[T comparable](items []T) Set[T]
 ```
 
 <b>示例:</b>
@@ -93,7 +93,7 @@ import (
 )
 
 func main() {
-    st := set.NewSetFromSlice([]int{1, 2, 2, 3})
+    st := set.FromSlice([]int{1, 2, 2, 3})
     fmt.Println(st.Values()) //1,2,3
 }
 ```
@@ -119,7 +119,7 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int](1,2,2,3)
+    st := set.New[int](1,2,2,3)
     fmt.Println(st.Values()) //1,2,3
 }
 ```
@@ -145,7 +145,7 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int]()
+    st := set.New[int]()
     st.Add(1, 2, 3)
 
     fmt.Println(st.Values()) //1,2,3
@@ -173,7 +173,7 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int]()
+    st := set.New[int]()
     st.Add(1, 2, 3)
 
     r1 := st.AddIfNotExist(1)
@@ -206,7 +206,7 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int]()
+    st := set.New[int]()
     st.Add(1, 2)
 
     ok := st.AddIfNotExistBy(3, func(val int) bool {
@@ -245,7 +245,7 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int]()
+    st := set.New[int]()
     st.Add(1, 2, 3)
 
     set.Delete(3)
@@ -274,7 +274,7 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int]()
+    st := set.New[int]()
     st.Add(1, 2, 3)
 
     fmt.Println(st.Contain(1)) //true
@@ -303,9 +303,9 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet(1, 2)
-    set3 := set.NewSet(1, 2, 3, 4)
+    set1 := set.New(1, 2, 3)
+    set2 := set.New(1, 2)
+    set3 := set.New(1, 2, 3, 4)
 
     fmt.Println(set1.ContainAll(set2)) //true
     fmt.Println(set1.ContainAll(set3)) //false
@@ -333,7 +333,7 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
+    set1 := set.New(1, 2, 3)
 
     fmt.Println(set1.Size()) //3
 }
@@ -360,7 +360,7 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
+    set1 := set.New(1, 2, 3)
     set2 := set1.Clone()
 
     fmt.Println(set1.Size() == set2.Size()) //true
@@ -389,9 +389,9 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet(1, 2, 3)
-    set3 := set.NewSet(1, 2, 3, 4)
+    set1 := set.New(1, 2, 3)
+    set2 := set.New(1, 2, 3)
+    set3 := set.New(1, 2, 3, 4)
 
     fmt.Println(set1.Equal(set2)) //true
     fmt.Println(set1.Equal(set3)) //false
@@ -419,7 +419,7 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
+    set1 := set.New(1, 2, 3)
     arr := []int{}
     set.Iterate(func(item int) {
         arr = append(arr, item)
@@ -450,7 +450,7 @@ import (
 )
 
 func main() {
-    s := set.NewSet(1, 2, 3, 4, 5)
+    s := set.New(1, 2, 3, 4, 5)
 
     var sum int
 
@@ -487,8 +487,8 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet()
+    set1 := set.New(1, 2, 3)
+    set2 := set.New()
 
     fmt.Println(set1.IsEmpty()) //false
     fmt.Println(set2.IsEmpty()) //true
@@ -516,8 +516,8 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet(2, 3, 4, 5)
+    set1 := set.New(1, 2, 3)
+    set2 := set.New(2, 3, 4, 5)
     set3 := set1.Union(set2)
 
     fmt.Println(set3.Values()) //1,2,3,4,5
@@ -545,8 +545,8 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet(2, 3, 4, 5)
+    set1 := set.New(1, 2, 3)
+    set2 := set.New(2, 3, 4, 5)
     set3 := set1.Intersection(set2)
 
     fmt.Println(set3.Values()) //2,3
@@ -574,8 +574,8 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet(2, 3, 4, 5)
+    set1 := set.New(1, 2, 3)
+    set2 := set.New(2, 3, 4, 5)
     set3 := set1.SymmetricDifference(set2)
 
     fmt.Println(set3.Values()) //1,4,5
@@ -603,9 +603,9 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet(2, 3, 4, 5)
-    set3 := set.NewSet(2, 3)
+    set1 := set.New(1, 2, 3)
+    set2 := set.New(2, 3, 4, 5)
+    set3 := set.New(2, 3)
 
     res1 := set1.Minus(set2)
     fmt.Println(res1.Values()) //1
@@ -636,7 +636,7 @@ import (
 )
 
 func main() {
-    s := set.NewSet[int]()
+    s := set.New[int]()
     s.Add(1)
     s.Add(2)
     s.Add(3)

docs/api/packages/fileutil.md

@@ -759,7 +759,7 @@ func main() {
 func WriteMapsToCsv(filepath string, records []map[string]any, appendToExistingFile bool, delimiter rune, headers ...[]string) error
 ```
 
-<b>示例:</b>
+<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/umAIomZFV1c)</span></b>
 
 ```go
 package main
@@ -782,7 +782,7 @@ func main() {
     }
 
     headers := []string{"Name", "Age", "Gender"}
-    err := WriteMapsToCsv(csvFilePath, records, false, ';', headers)
+    err := fileutil.WriteMapsToCsv(csvFilePath, records, false, ';', headers)
 
     if err != nil {
         log.Fatal(err)

docs/api/packages/function.md

@@ -7,6 +7,7 @@ function 函数包控制函数执行流程，包含部分函数式编程。
 ## 源码:
 
 -   [https://github.com/duke-git/lancet/blob/main/function/function.go](https://github.com/duke-git/lancet/blob/main/function/function.go)
+-   [https://github.com/duke-git/lancet/blob/main/function/predicate.go](https://github.com/duke-git/lancet/blob/main/function/predicate.go)
 -   [https://github.com/duke-git/lancet/blob/main/function/watcher.go](https://github.com/duke-git/lancet/blob/main/function/watcher.go)
 
 <div STYLE="page-break-after: always;"></div>
@@ -32,6 +33,10 @@ import (
 -   [Schedule](#Schedule)
 -   [Pipeline](#Pipeline)
 -   [Watcher](#Watcher)
+-   [And](#And)
+-   [Or](#Or)
+-   [Negate](#Negate)
+-   [Nor](#Nor)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -404,3 +409,157 @@ func longRunningTask() {
 }
 
 ```
+
+### <span id="And">And</span>
+
+<p>返回一个复合谓词判断函数，该判断函数表示一组谓词的逻辑and操作。只有当所有谓词判断函数对于给定的值都返回true时，返回true, 否则返回false。</p>
+
+<b>函数签名:</b>
+
+```go
+func And[T any](predicates ...func(T) bool) func(T) bool
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/function"
+)
+
+func main() {
+    isNumericAndLength5 := function.And(
+        func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+        func(s string) bool { return len(s) == 5 },
+    )
+
+    fmt.Println(isNumericAndLength5("12345"))
+    fmt.Println(isNumericAndLength5("1234"))
+    fmt.Println(isNumericAndLength5("abcde"))
+
+    // Output:
+    // true
+    // false
+    // false
+}
+```
+
+### <span id="Or">Or</span>
+
+<p>返回一个复合谓词判断函数，该判断函数表示一组谓词的逻辑or操作。只有当所有谓词判断函数对于给定的值都返回false时，返回false, 否则返回true。</p>
+
+<b>函数签名:</b>
+
+```go
+func Or[T any](predicates ...func(T) bool) func(T) bool
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/function"
+)
+
+func main() {
+    containsDigitOrSpecialChar := function.Or(
+        func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+        func(s string) bool { return strings.ContainsAny(s, "!@#$%") },
+    )
+
+    fmt.Println(containsDigitOrSpecialChar("hello!"))
+    fmt.Println(containsDigitOrSpecialChar("hello"))
+
+    // Output:
+    // true
+    // false
+}
+```
+
+### <span id="Negate">Negate</span>
+
+<p>返回一个谓词函数，该谓词函数表示当前谓词的逻辑否定。</p>
+
+<b>函数签名:</b>
+
+```go
+func Negate[T any](predicate func(T) bool) func(T) bool
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/function"
+)
+
+func main() {
+    // Define some simple predicates for demonstration
+    isUpperCase := func(s string) bool {
+        return strings.ToUpper(s) == s
+    }
+    isLowerCase := func(s string) bool {
+        return strings.ToLower(s) == s
+    }
+    isMixedCase := function.Negate(function.Or(isUpperCase, isLowerCase))
+
+    fmt.Println(isMixedCase("ABC"))
+    fmt.Println(isMixedCase("AbC"))
+
+    // Output:
+    // false
+    // true
+}
+```
+
+
+### <span id="Nor">Nor</span>
+
+<p>返回一个组合谓词函数，表示给定值上所有谓词逻辑非或 (nor) 的结果。只有当所有谓词函数对给定值都返回false时，该组合谓词函数才返回true。</p>
+
+<b>函数签名:</b>
+
+```go
+func Nor[T any](predicates ...func(T) bool) func(T) bool
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/function"
+)
+
+func main() {
+    match := function.Nor(
+        func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+        func(s string) bool { return len(s) == 5 },
+    )
+
+    fmt.Println(match("dbcdckkeee"))
+
+
+    match = function.Nor(
+        func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+        func(s string) bool { return len(s) == 5 },
+    )
+
+    fmt.Println(match("0123456789"))
+
+    // Output:
+    // true
+    // false
+}
+```

docs/api/packages/slice.md

@@ -525,7 +525,7 @@ func main() {
 func DeleteAt[T any](slice []T, index int) []T
 ```
 
-<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/pJ-d6MUWcvK)</span></b>
+<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/800B1dPBYyd)</span></b>
 
 ```go
 import (
@@ -565,7 +565,7 @@ func main() {
 func DeleteRange[T any](slice []T, start, end int) []T 
 ```
 
-<b>示例:</b>
+<b>示例:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/945HwiNrnle)</span></b>
 
 ```go
 import (

docs/api/packages/strutil.md

@@ -60,6 +60,7 @@ import (
 -   [ContainsAll](#ContainsAll)
 -   [ContainsAny](#ContainsAny)
 -   [RemoveWhiteSpace](#RemoveWhiteSpace)
+-   [SubInBetween](#SubInBetween)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -1096,10 +1097,10 @@ import (
 
 func main() {
     result1 := strutil.IsNotBlank("")
-    result2 := strutil.IsNotBlank("	")
+    result2 := strutil.IsNotBlank("    ")
     result3 := strutil.IsNotBlank("\t\v\f\n")
     result4 := strutil.IsNotBlank(" 中文")
-    result5 := strutil.IsNotBlank(" 	world	")
+    result5 := strutil.IsNotBlank("     world    ")
     
     fmt.Println(result1)
     fmt.Println(result2)
@@ -1462,3 +1463,36 @@ func main() {
     // hello world
 }
 ```
+
+### <span id="SubInBetween">SubInBetween</span>
+
+<p>获取字符串中指定的起始字符串start和终止字符串end直接的子字符串。</p>
+
+<b>函数签名:</b>
+
+```go
+func SubInBetween(str string, start string, end string) string
+```
+
+<b>示例:</b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/strutil"
+)
+
+func main() {
+    str := "abcde"
+
+    result1 := strutil.SubInBetween(str, "", "de")
+    result2 := strutil.SubInBetween(str, "a", "d")
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+
+    // Output:
+    // abc
+    // bc
+}
+```

docs/en/api/packages/datastructure/copyonwritelist.md

@@ -26,6 +26,8 @@ import (
 -   [Remove](#Remove)
 -   [IndexOf](#IndexOf)
 -   [LastIndexOf](#LastIndexOf)
+-   [IndexOfFunc](#IndexOfFunc)
+-   [LastIndexOfFunc](#LastIndexOfFunc)
 -   [IsEmpty](#IsEmpty)
 -   [Contain](#Contain)
 -   [ValueOf](#ValueOf)
@@ -197,6 +199,59 @@ func main() {
 
 ```
 
+
+### <span id="IndexOfFunc">IndexOfFunc</span>
+<p> IndexOfFunc returns the first index satisfying the functional predicate f(v) bool. if not found return -1.</p>
+
+<b>Signature:</b>
+
+```go
+func (l *CopyOnWriteList[T]) IndexOfFunc(f func(T) bool) int 
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/list"
+)
+
+func main() {
+    l := list.NewCopyOnWriteList([]int{1, 2, 3})
+
+    fmt.Println(l.IndexOfFunc(func(a int) bool { return a == 1 })) //0
+    fmt.Println(l.IndexOfFunc(func(a int) bool { return a == 0 })) //-1
+}
+```
+
+### <span id="LastIndexOfFunc">LastIndexOfFunc</span>
+<p>LastIndexOfFunc returns the index of the last occurrence of the value in this list satisfying the functional predicate f(T) bool. if not found return -1.</p>
+
+<b>Signature:</b>
+
+```go
+func (l *CopyOnWriteList[T]) LastIndexOfFunc(f func(T) bool) int
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/list"
+)
+
+func main() {
+    l := list.NewCopyOnWriteList([]int{1, 2, 3, 1})
+
+    fmt.Println(l.LastIndexOfFunc(func(a int) bool { return a == 1 })) // 3
+    fmt.Println(l.LastIndexOfFunc(func(a int) bool { return a == 0 })) //-1
+}
+```
+
 ### IsEmpty
 
 Returns true if this list does not contain any elements.

docs/en/api/packages/datastructure/optional.md

@@ -0,0 +1,416 @@
+# Optional
+Optional is a type that may or may not contain a non-nil value.
+
+<div STYLE="page-break-after: always;"></div>
+
+## Source
+
+- [https://github.com/duke-git/lancet/blob/main/datastructure/optional/optional.go](https://github.com/duke-git/lancet/blob/main/datastructure/optional/optional.go)
+
+
+<div STYLE="page-break-after: always;"></div>
+
+## Usage
+```go
+import (
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+```
+
+<div STYLE="page-break-after: always;"></div>
+
+## Index
+
+- [Of](#Of)
+- [FromNillable](#FromNillable)
+- [Default](#Default)
+- [IsNotNil](#IsNotNil)
+- [IsNil](#IsNil)
+- [IsNotNil](#IsNotNil)
+- [IfNotNilOrElse](#IfNotNilOrElse)
+- [Umwarp](#Umwarp)
+- [OrElse](#OrElse)
+- [OrElseGet](#OrElseGet)
+- [OrElseTrigger](#OrElseTrigger)
+
+
+
+<div STYLE="page-break-after: always;"></div>
+
+## Documentation
+
+### <span id="Of">Of</span>
+<p>Returns an Optional with a non-nil value.</p>
+
+<b>Signature:</b>
+
+```go
+func Of[T any](value T) Optional[T]
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    value := 42
+    opt := optional.Of(value)
+
+    fmt.Println(opt.Get())
+
+    // Output:
+    // 42
+}
+```
+
+### <span id="FromNillable">FromNillable</span>
+<p>Returns an Optional for a given value, which may be nil.</p>
+
+<b>Signature:</b>
+
+```go
+func FromNillable[T any](value *T) Optional[T]
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    var value *int = nil
+    opt := optional.FromNillable(value)
+
+    fmt.Println(opt.IsNotNil())
+
+    value = new(int)
+    *value = 42
+    opt = optional.FromNillable(value)
+
+    fmt.Println(opt.IsNotNil())
+
+
+    // Output:
+    // false
+    // true
+}
+```
+
+
+### <span id="Default">Default</span>
+<p>Returns an default Optional instance.</p>
+
+<b>Signature:</b>
+
+```go
+func Default[T any]() Optional[T]
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    optDefault := optional.Default[int]()
+    fmt.Println(optDefault.IsNil())
+
+    // Output:
+    // true
+}
+```
+
+
+### <span id="IsNil">IsNil</span>
+<p>Checks if the Optional is nil.</p>
+
+<b>Signature:</b>
+
+```go
+func (o Optional[T]) IsNil() bool
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    optDefault := optional.Default[int]()
+    fmt.Println(optDefault.IsNil())
+
+    // Output:
+    // true
+}
+```
+
+
+### <span id="IsNotNil">IsNotNil</span>
+<p>Checks if there is a value not nil.</p>
+
+<b>Signature:</b>
+
+```go
+func (o Optional[T]) IsNotNil() bool
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    var value *int = nil
+    opt := optional.FromNillable(value)
+
+    fmt.Println(opt.IsNotNil())
+
+    value = new(int)
+    *value = 42
+    opt = optional.FromNillable(value)
+
+    fmt.Println(opt.IsNotNil())
+
+
+    // Output:
+    // false
+    // true
+}
+```
+
+
+### <span id="IfNotNil">IfNotNil</span>
+<p>Performs the given action with the value if a value is present.</p>
+
+<b>Signature:</b>
+
+```go
+func (o Optional[T]) IfNotNil(action func(value T))
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+     "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    called := false
+    action := func(value int) { called = true }
+
+    optDefault := optional.Default[int]()
+    optDefault.IfNotNil(action)
+
+    fmt.Println(called)
+
+    called = false // Reset for next test
+    optWithValue := optional.Of(42)
+    optWithValue.IfNotNil(action)
+
+    fmt.Println(optWithValue.IsNotNil())
+
+    // Output:
+    // false
+    // true
+}
+```
+
+
+### <span id="IfNotNilOrElse">IfNotNilOrElse</span>
+<p>Performs the action with the value if not nil, otherwise performs the fallback action.</p>
+
+<b>Signature:</b>
+
+```go
+func (o Optional[T]) IfNotNilOrElse(action func(value T), fallbackAction func())
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    calledWithValue := false
+    valueAction := func(value int) { calledWithValue = true }
+    emptyAction := func() { t.Errorf("Empty action should not be called when value is present") }
+
+    optWithValue := optional.Of(42)
+    optWithValue.IfNotNilOrElse(valueAction, emptyAction)
+
+    fmt.Println(calledWithValue)
+
+    calledWithEmpty := false
+    valueAction = func(value int) { t.Errorf("Value action should not be called when value is not present") }
+    emptyAction = func() { calledWithEmpty = true }
+
+    optDefault := optional.Default[int]()
+    optDefault.IfNotNilOrElse(valueAction, emptyAction)
+
+    fmt.Println(calledWithEmpty)
+
+    // Output:
+    // true
+    // true
+}
+```
+
+### <span id="Unwrap">Unwrap</span>
+<p>Returns the value if not nil, otherwise panics.</p>
+
+<b>Signature:</b>
+
+```go
+func (o Optional[T]) Unwrap() T
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    value := 42
+    opt := optional.Of(value)
+
+    fmt.Println(opt.Unwrap())
+
+    // Output:
+    // 42
+}
+```
+
+
+### <span id="OrElse">OrElse</span>
+<p>Returns the value if not nill, otherwise returns other.</p>
+
+<b>Signature:</b>
+
+```go
+func (o Optional[T]) OrElse(other T) T
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    optDefault := optional.Default[int]()
+    val := optDefault.OrElse(100)
+    fmt.Println(val)
+
+    optWithValue := optional.Of(42)
+    val = optWithValue.OrElse(100)
+    fmt.Println(val)
+
+    // Output:
+    // 100
+    // 42
+}
+```
+
+
+### <span id="OrElseGet">OrElseGet</span>
+<p>Returns the value if not nil, otherwise invokes action and returns the result.</p>
+
+<b>Signature:</b>
+
+```go
+func (o Optional[T]) OrElseGet(action func() T) T
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    optDefault := optional.Default[int]()
+    action := func() int { return 100 }
+
+    val := optDefault.OrElseGet(action)
+    fmt.Println(val)
+
+    // Output:
+    // 100
+}
+```
+
+
+### <span id="OrElseTrigger">OrElseTrigger</span>
+<p>Returns the value if present, otherwise returns an error.</p>
+
+<b>Signature:</b>
+
+```go
+ OrElseTrigger(errorHandler func() error) (T, error)
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/datastructure/optional"
+)
+
+func main() {
+    optDefault := optional.Default[int]()
+    _, err := optDefault.OrElseTrigger(func() error { return errors.New("no value") })
+    
+    fmt.Println(err.Error())
+
+    optWithValue := optional.Of(42)
+    val, err := optWithValue.OrElseTrigger(func() error { return errors.New("no value") })
+
+    fmt.Println(val)
+    fmt.Println(err)
+
+    // Output:
+    // no value
+    // 42
+    // nil
+}
+```

docs/en/api/packages/datastructure/set.md

@@ -22,8 +22,8 @@ import (
 
 ## Index
 
--   [NewSet](#NewSet)
--   [NewSetFromSlice](#NewSetFromSlice)
+-   [New](#New)
+-   [FromSlice](#FromSlice)
 -   [Values](#Values)
 -   [Add](#Add)
 -   [AddIfNotExist](#AddIfNotExist)
@@ -46,7 +46,7 @@ import (
 
 ## Documentation
 
-### <span id="NewSet">NewSet</span>
+### <span id="New">New</span>
 
 <p>Create a set instance</p>
 
@@ -54,7 +54,7 @@ import (
 
 ```go
 type Set[T comparable] map[T]bool
-func NewSet[T comparable](items ...T) Set[T]
+func New[T comparable](items ...T) Set[T]
 ```
 
 <b>Example:</b>
@@ -68,19 +68,19 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int](1,2,2,3)
+    st := set.New[int](1,2,2,3)
     fmt.Println(st.Values()) //1,2,3
 }
 ```
 
-### <span id="NewSetFromSlice">NewSetFromSlice</span>
+### <span id="FromSlice">FromSlice</span>
 
 <p>Create a set from slice</p>
 
 <b>Signature:</b>
 
 ```go
-func NewSetFromSlice[T comparable](items []T) Set[T]
+func FromSlice[T comparable](items []T) Set[T]
 ```
 
 <b>Example:</b>
@@ -94,7 +94,7 @@ import (
 )
 
 func main() {
-    st := set.NewSetFromSlice([]int{1, 2, 2, 3})
+    st := set.FromSlice([]int{1, 2, 2, 3})
     fmt.Println(st.Values()) //1,2,3
 }
 ```
@@ -120,7 +120,7 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int](1,2,2,3)
+    st := set.New[int](1,2,2,3)
     fmt.Println(st.Values()) //1,2,3
 }
 ```
@@ -146,7 +146,7 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int]()
+    st := set.New[int]()
     st.Add(1, 2, 3)
 
     fmt.Println(st.Values()) //1,2,3
@@ -174,7 +174,7 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int]()
+    st := set.New[int]()
     st.Add(1, 2, 3)
 
     r1 := st.AddIfNotExist(1)
@@ -207,7 +207,7 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int]()
+    st := set.New[int]()
     st.Add(1, 2)
 
     ok := st.AddIfNotExistBy(3, func(val int) bool {
@@ -246,7 +246,7 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int]()
+    st := set.New[int]()
     st.Add(1, 2, 3)
 
     set.Delete(3)
@@ -275,7 +275,7 @@ import (
 )
 
 func main() {
-    st := set.NewSet[int]()
+    st := set.New[int]()
     st.Add(1, 2, 3)
 
     fmt.Println(st.Contain(1)) //true
@@ -304,9 +304,9 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet(1, 2)
-    set3 := set.NewSet(1, 2, 3, 4)
+    set1 := set.New(1, 2, 3)
+    set2 := set.New(1, 2)
+    set3 := set.New(1, 2, 3, 4)
 
     fmt.Println(set1.ContainAll(set2)) //true
     fmt.Println(set1.ContainAll(set3)) //false
@@ -334,7 +334,7 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
+    set1 := set.New(1, 2, 3)
 
     fmt.Println(set1.Size()) //3
 }
@@ -361,7 +361,7 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
+    set1 := set.New(1, 2, 3)
     set2 := set1.Clone()
 
     fmt.Println(set1.Size() == set2.Size()) //true
@@ -390,9 +390,9 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet(1, 2, 3)
-    set3 := set.NewSet(1, 2, 3, 4)
+    set1 := set.New(1, 2, 3)
+    set2 := set.New(1, 2, 3)
+    set3 := set.New(1, 2, 3, 4)
 
     fmt.Println(set1.Equal(set2)) //true
     fmt.Println(set1.Equal(set3)) //false
@@ -420,7 +420,7 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
+    set1 := set.New(1, 2, 3)
     arr := []int{}
     set.Iterate(func(item int) {
         arr = append(arr, item)
@@ -451,7 +451,7 @@ import (
 )
 
 func main() {
-    s := set.NewSet(1, 2, 3, 4, 5)
+    s := set.New(1, 2, 3, 4, 5)
 
     var sum int
 
@@ -488,8 +488,8 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet()
+    set1 := set.New(1, 2, 3)
+    set2 := set.New()
 
     fmt.Println(set1.IsEmpty()) //false
     fmt.Println(set2.IsEmpty()) //true
@@ -517,8 +517,8 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet(2, 3, 4, 5)
+    set1 := set.New(1, 2, 3)
+    set2 := set.New(2, 3, 4, 5)
     set3 := set1.Union(set2)
 
     fmt.Println(set3.Values()) //1,2,3,4,5
@@ -546,8 +546,8 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet(2, 3, 4, 5)
+    set1 := set.New(1, 2, 3)
+    set2 := set.New(2, 3, 4, 5)
     set3 := set1.Intersection(set2)
 
     fmt.Println(set3.Values()) //2,3
@@ -575,8 +575,8 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet(2, 3, 4, 5)
+    set1 := set.New(1, 2, 3)
+    set2 := set.New(2, 3, 4, 5)
     set3 := set1.SymmetricDifference(set2)
 
     fmt.Println(set3.Values()) //1,4,5
@@ -604,9 +604,9 @@ import (
 )
 
 func main() {
-    set1 := set.NewSet(1, 2, 3)
-    set2 := set.NewSet(2, 3, 4, 5)
-    set3 := set.NewSet(2, 3)
+    set1 := set.New(1, 2, 3)
+    set2 := set.New(2, 3, 4, 5)
+    set3 := set.New(2, 3)
 
     res1 := set1.Minus(set2)
     fmt.Println(res1.Values()) //1
@@ -637,7 +637,7 @@ import (
 )
 
 func main() {
-    s := set.NewSet[int]()
+    s := set.New[int]()
     s.Add(1)
     s.Add(2)
     s.Add(3)

docs/en/api/packages/fileutil.md

@@ -45,7 +45,6 @@ import (
 -   [Sha](#Sha)
 -   [ReadCsvFile](#ReadCsvFile)
 -   [WriteCsvFile](#WriteCsvFile)
--   [WriteCsvFile](#WriteCsvFile)
 -   [WriteMapsToCsv](#WriteMapsToCsv)
 -   [WriteStringToFile](#WriteStringToFile)
 -   [WriteBytesToFile](#WriteBytesToFile)
@@ -760,7 +759,7 @@ func main() {
 func WriteMapsToCsv(filepath string, records []map[string]any, appendToExistingFile bool, delimiter rune, headers ...[]string) error
 ```
 
-<b>Example:</b>
+<b>Example:<span style="float:right;display:inline-block;">[运行](https://go.dev/play/p/umAIomZFV1c)</span></b>
 
 ```go
 package main

docs/en/api/packages/function.md

@@ -7,6 +7,7 @@ Package function can control the flow of function execution and support part of
 ## Source:
 
 -   [https://github.com/duke-git/lancet/blob/main/function/function.go](https://github.com/duke-git/lancet/blob/main/function/function.go)
+-   [https://github.com/duke-git/lancet/blob/main/function/predicate.go](https://github.com/duke-git/lancet/blob/main/function/predicate.go)
 -   [https://github.com/duke-git/lancet/blob/main/function/watcher.go](https://github.com/duke-git/lancet/blob/main/function/watcher.go)
 
 <div STYLE="page-break-after: always;"></div>
@@ -32,6 +33,10 @@ import (
 -   [Schedule](#Schedule)
 -   [Pipeline](#Pipeline)
 -   [Watcher](#Watcher)
+-   [And](#And)
+-   [Or](#Or)
+-   [Negate](#Negate)
+-   [Nor](#Nor)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -403,3 +408,158 @@ func longRunningTask() {
 }
 
 ```
+
+
+### <span id="And">And</span>
+
+<p>Returns a composed predicate that represents the logical AND of a list of predicates. It evaluates to true only if all predicates evaluate to true for the given value.</p>
+
+<b>Signature:</b>
+
+```go
+func And[T any](predicates ...func(T) bool) func(T) bool
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/function"
+)
+
+func main() {
+    isNumericAndLength5 := function.And(
+        func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+        func(s string) bool { return len(s) == 5 },
+    )
+
+    fmt.Println(isNumericAndLength5("12345"))
+    fmt.Println(isNumericAndLength5("1234"))
+    fmt.Println(isNumericAndLength5("abcde"))
+
+    // Output:
+    // true
+    // false
+    // false
+}
+```
+
+### <span id="Or">Or</span>
+
+<p>Returns a composed predicate that represents the logical OR of a list of predicates. It evaluates to true if at least one of the predicates evaluates to true for the given value.</p>
+
+<b>Signature:</b>
+
+```go
+func Or[T any](predicates ...func(T) bool) func(T) bool
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/function"
+)
+
+func main() {
+    containsDigitOrSpecialChar := function.Or(
+        func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+        func(s string) bool { return strings.ContainsAny(s, "!@#$%") },
+    )
+
+    fmt.Println(containsDigitOrSpecialChar("hello!"))
+    fmt.Println(containsDigitOrSpecialChar("hello"))
+
+    // Output:
+    // true
+    // false
+}
+```
+
+### <span id="Negate">Negate</span>
+
+<p>Returns a predicate that represents the logical negation of this predicate.</p>
+
+<b>Signature:</b>
+
+```go
+func Negate[T any](predicate func(T) bool) func(T) bool
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/function"
+)
+
+func main() {
+    // Define some simple predicates for demonstration
+    isUpperCase := func(s string) bool {
+        return strings.ToUpper(s) == s
+    }
+    isLowerCase := func(s string) bool {
+        return strings.ToLower(s) == s
+    }
+    isMixedCase := function.Negate(function.Or(isUpperCase, isLowerCase))
+
+    fmt.Println(isMixedCase("ABC"))
+    fmt.Println(isMixedCase("AbC"))
+
+    // Output:
+    // false
+    // true
+}
+```
+
+
+### <span id="Nor">Nor</span>
+
+<p>Returns a composed predicate that represents the logical NOR of a list of predicates. It evaluates to true only if all predicates evaluate to false for the given value.</p>
+
+<b>Signature:</b>
+
+```go
+func Nor[T any](predicates ...func(T) bool) func(T) bool
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/function"
+)
+
+func main() {
+    match := function.Nor(
+        func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+        func(s string) bool { return len(s) == 5 },
+    )
+
+    fmt.Println(match("dbcdckkeee"))
+
+
+    match = function.Nor(
+        func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+        func(s string) bool { return len(s) == 5 },
+    )
+
+    fmt.Println(match("0123456789"))
+
+    // Output:
+    // true
+    // false
+}
+```

docs/en/api/packages/slice.md

@@ -524,7 +524,7 @@ func main() {
 func DeleteAt[T any](slice []T, index int)
 ```
 
-<b>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/pJ-d6MUWcvK)</span></b>
+<b>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/800B1dPBYyd)</span></b>
 
 ```go
 import (
@@ -563,7 +563,7 @@ func main() {
 func DeleteRange[T any](slice []T, start, end int) []T 
 ```
 
-<b>Example:</b>
+<b>Example:<span style="float:right;display:inline-block;">[Run](https://go.dev/play/p/945HwiNrnle)</span></b>
 
 ```go
 import (
@@ -574,11 +574,11 @@ import (
 func main() {
     chars := []string{"a", "b", "c", "d", "e"}
 
-    result1 := DeleteRange(chars, 0, 0)
-    result2 := DeleteRange(chars, 0, 1)
-    result3 := DeleteRange(chars, 0, 3)
-    result4 := DeleteRange(chars, 0, 4)
-    result5 := DeleteRange(chars, 0, 5)
+    result1 := slice.DeleteRange(chars, 0, 0)
+    result2 := slice.DeleteRange(chars, 0, 1)
+    result3 := slice.DeleteRange(chars, 0, 3)
+    result4 := slice.DeleteRange(chars, 0, 4)
+    result5 := slice.DeleteRange(chars, 0, 5)
 
     fmt.Println(result1)
     fmt.Println(result2)

docs/en/api/packages/strutil.md

@@ -1463,3 +1463,37 @@ func main() {
     // hello world
 }
 ```
+
+
+### <span id="SubInBetween">SubInBetween</span>
+
+<p>Return substring between the start and end position(excluded) of source string.</p>
+
+<b>Signature:</b>
+
+```go
+func SubInBetween(str string, start string, end string) string
+```
+
+<b>Example:</b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/strutil"
+)
+
+func main() {
+    str := "abcde"
+
+    result1 := strutil.SubInBetween(str, "", "de")
+    result2 := strutil.SubInBetween(str, "a", "d")
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+
+    // Output:
+    // abc
+    // bc
+}
+```

fileutil/file.go

@@ -65,8 +65,8 @@ func (f *FileReader) Offset() int64 {
 	return f.offset
 }
 
-// Seek sets the current offset of the reading
-func (f *FileReader) Seek(offset int64) error {
+// SeekOffset sets the current offset of the reading
+func (f *FileReader) SeekOffset(offset int64) error {
 	_, err := f.file.Seek(offset, 0)
 	if err != nil {
 		return err
@@ -754,7 +754,7 @@ func escapeCSVField(field string, delimiter rune) string {
 }
 
 // WriteMapsToCsv write slice of map to csv file.
-// Play: todo
+// Play: https://go.dev/play/p/umAIomZFV1c
 // filepath: Path to the CSV file.
 // records: Slice of maps to be written. the value of map should be basic type.
 // the maps will be sorted by key in alphabeta order, then be written into csv file.

fileutil/file_test.go

@@ -534,7 +534,7 @@ func TestReadlineFile(t *testing.T) {
 		if !ok {
 			t.Fail()
 		}
-		if err = reader.Seek(offset); err != nil {
+		if err = reader.SeekOffset(offset); err != nil {
 			t.Fail()
 		}
 		lineRead, err := reader.ReadLine()

function/predicate.go

@@ -0,0 +1,75 @@
+package function
+
+// And returns a composed predicate that represents the logical AND of a list of predicates.
+// It evaluates to true only if all predicates evaluate to true for the given value.
+func And[T any](predicates ...func(T) bool) func(T) bool {
+	if len(predicates) < 2 {
+		panic("programming error: predicates count must be at least 2")
+	}
+	return func(value T) bool {
+		for _, predicate := range predicates {
+			if !predicate(value) {
+				return false // Short-circuit on the first false predicate
+			}
+		}
+		return true // True if all predicates are true
+	}
+}
+
+// Negate returns a predicate that represents the logical negation of this predicate.
+func Negate[T any](predicate func(T) bool) func(T) bool {
+	return func(value T) bool {
+		return !predicate(value)
+	}
+}
+
+// Or returns a composed predicate that represents the logical OR of a list of predicates.
+// It evaluates to true if at least one of the predicates evaluates to true for the given value.
+func Or[T any](predicates ...func(T) bool) func(T) bool {
+	if len(predicates) < 2 {
+		panic("programming error: predicates count must be at least 2")
+	}
+	return func(value T) bool {
+		for _, predicate := range predicates {
+			if predicate(value) {
+				return true // Short-circuit on the first true predicate
+			}
+		}
+		return false // False if all predicates are false
+	}
+}
+
+// Nor returns a composed predicate that represents the logical NOR of a list of predicates.
+// It evaluates to true only if all predicates evaluate to false for the given value.
+func Nor[T any](predicates ...func(T) bool) func(T) bool {
+	if len(predicates) < 2 {
+		panic("programming error: predicates count must be at least 2")
+	}
+	return func(value T) bool {
+		for _, predicate := range predicates {
+			if predicate(value) {
+				return false // If any predicate evaluates to true, the NOR result is false
+			}
+		}
+		return true // Only returns true if all predicates evaluate to false
+	}
+}
+
+// Xnor returns a composed predicate that represents the logical XNOR of a list of predicates.
+// It evaluates to true only if all predicates evaluate to true or false for the given value.
+func Xnor[T any](predicates ...func(T) bool) func(T) bool {
+	if len(predicates) < 2 {
+		panic("programming error: predicates count must be at least 2")
+	}
+	return func(value T) bool {
+		trueCount := 0
+		for _, predicate := range predicates {
+			if predicate(value) {
+				trueCount++
+			}
+		}
+		// XNOR is true if either all predicates are true or all are false
+		// This is the same as saying trueCount is 0 (all false) or trueCount is len(predicates) (all true)
+		return trueCount == 0 || trueCount == len(predicates)
+	}
+}

function/predicate_example_test.go

@@ -0,0 +1,112 @@
+package function
+
+import (
+	"fmt"
+	"strings"
+)
+
+func ExampleNegate() {
+	// Define some simple predicates for demonstration
+	isUpperCase := func(s string) bool {
+		return strings.ToUpper(s) == s
+	}
+	isLowerCase := func(s string) bool {
+		return strings.ToLower(s) == s
+	}
+	isMixedCase := Negate(Or(isUpperCase, isLowerCase))
+
+	fmt.Println(isMixedCase("ABC"))
+	fmt.Println(isMixedCase("AbC"))
+
+	// Output:
+	// false
+	// true
+}
+
+func ExampleOr() {
+	containsDigitOrSpecialChar := Or(
+		func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+		func(s string) bool { return strings.ContainsAny(s, "!@#$%") },
+	)
+
+	fmt.Println(containsDigitOrSpecialChar("hello!"))
+	fmt.Println(containsDigitOrSpecialChar("hello"))
+
+	// Output:
+	// true
+	// false
+}
+
+func ExampleAnd() {
+	isNumericAndLength5 := And(
+		func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+		func(s string) bool { return len(s) == 5 },
+	)
+
+	fmt.Println(isNumericAndLength5("12345"))
+	fmt.Println(isNumericAndLength5("1234"))
+	fmt.Println(isNumericAndLength5("abcde"))
+
+	// Output:
+	// true
+	// false
+	// false
+}
+
+func ExampleNor() {
+	match := Nor(
+		func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+		func(s string) bool { return len(s) == 5 },
+	)
+
+	fmt.Println(match("dbcdckkeee"))
+
+	match = Nor(
+		func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+		func(s string) bool { return len(s) == 5 },
+	)
+
+	fmt.Println(match("0123456789"))
+
+	// Output:
+	// true
+	// false
+}
+
+func ExampleXnor() {
+	isEven := func(i int) bool { return i%2 == 0 }
+	isPositive := func(i int) bool { return i > 0 }
+
+	match := Xnor(isEven, isPositive)
+
+	fmt.Println(match(2))
+	fmt.Println(match(-3))
+	fmt.Println(match(3))
+
+	// Output:
+	// true
+	// true
+	// false
+}
+
+// func ExamplePredicatesMix() {
+// 	a := Or(
+// 		func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+// 		func(s string) bool { return strings.ContainsAny(s, "!") },
+// 	)
+
+// 	b := And(
+// 		func(s string) bool { return strings.ContainsAny(s, "hello") },
+// 		func(s string) bool { return strings.ContainsAny(s, "!") },
+// 	)
+
+// 	c := Negate(And(a, b))
+// 	fmt.Println(c("hello!"))
+
+// 	c = Nor(a, b)
+// 	fmt.Println(c("hello!"))
+
+// 	// Output:
+// 	// false
+// 	// false
+// }

function/predicate_test.go

@@ -0,0 +1,116 @@
+package function
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/duke-git/lancet/v2/internal"
+)
+
+func TestPredicatesNegatePure(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestPredicatesNegatePure")
+
+	// Define some simple predicates for demonstration
+	isUpperCase := func(s string) bool {
+		return strings.ToUpper(s) == s
+	}
+	isLowerCase := func(s string) bool {
+		return strings.ToLower(s) == s
+	}
+	isMixedCase := Negate(Or(isUpperCase, isLowerCase))
+
+	assert.ShouldBeFalse(isMixedCase("ABC"))
+	assert.ShouldBeTrue(isMixedCase("AbC"))
+}
+
+func TestPredicatesOrPure(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestPredicatesOrPure")
+
+	containsDigitOrSpecialChar := Or(
+		func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+		func(s string) bool { return strings.ContainsAny(s, "!@#$%") },
+	)
+
+	assert.ShouldBeTrue(containsDigitOrSpecialChar("hello!"))
+	assert.ShouldBeFalse(containsDigitOrSpecialChar("hello"))
+}
+
+func TestPredicatesAndPure(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestPredicatesAndPure")
+
+	isNumericAndLength5 := And(
+		func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+		func(s string) bool { return len(s) == 5 },
+	)
+
+	assert.ShouldBeTrue(isNumericAndLength5("12345"))
+	assert.ShouldBeFalse(isNumericAndLength5("1234"))
+	assert.ShouldBeFalse(isNumericAndLength5("abcde"))
+}
+
+func TestPredicatesNorPure(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestPredicatesNorPure")
+
+	match := Nor(
+		func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+		func(s string) bool { return len(s) == 5 },
+	)
+
+	assert.ShouldBeTrue(match("dbcdckkeee"))
+
+	match = Nor(
+		func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+		func(s string) bool { return len(s) == 5 },
+	)
+
+	assert.ShouldBeFalse(match("0123456789"))
+}
+
+func TestPredicatesXnorPure(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestPredicatesXnorPure")
+
+	isEven := func(i int) bool { return i%2 == 0 }
+	isPositive := func(i int) bool { return i > 0 }
+
+	match := Xnor(isEven, isPositive)
+
+	assert.ShouldBeTrue(match(2))
+	assert.ShouldBeTrue(match(-3))
+	assert.ShouldBeFalse(match(3))
+}
+
+func TestPredicatesMix(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestPredicatesMix")
+
+	a := Or(
+		func(s string) bool { return strings.ContainsAny(s, "0123456789") },
+		func(s string) bool { return strings.ContainsAny(s, "!") },
+	)
+
+	b := And(
+		func(s string) bool { return strings.ContainsAny(s, "hello") },
+		func(s string) bool { return strings.ContainsAny(s, "!") },
+	)
+
+	c := Negate(And(a, b))
+
+	assert.ShouldBeFalse(c("hello!"))
+
+	c = Nor(a, b)
+	assert.ShouldBeFalse(c("hello!"))
+
+	c = Xnor(a, b)
+	assert.ShouldBeTrue(c("hello!"))
+}

internal/assert.go

@@ -37,6 +37,20 @@ func (a *Assert) Equal(expected, actual any) {
 	}
 }
 
+// ShouldBeFalse check if expected is false
+func (a *Assert) ShouldBeFalse(actual any) {
+	if compare(false, actual) != compareEqual {
+		makeTestFailed(a.T, a.CaseName, false, actual)
+	}
+}
+
+// ShouldBeTrue check if expected is true
+func (a *Assert) ShouldBeTrue(actual any) {
+	if compare(true, actual) != compareEqual {
+		makeTestFailed(a.T, a.CaseName, true, actual)
+	}
+}
+
 // NotEqual check if expected is not equal with actual
 func (a *Assert) NotEqual(expected, actual any) {
 	if compare(expected, actual) == compareEqual {

internal/assert_test.go

@@ -6,10 +6,11 @@ import (
 
 func TestAssert(t *testing.T) {
 	assert := NewAssert(t, "TestAssert")
+
 	assert.Equal(0, 0)
 	assert.NotEqual(1, 0)
-
 	assert.NotEqual("1", 1)
+
 	var uInt1 uint
 	var uInt2 uint
 	var uInt8 uint8
@@ -47,4 +48,11 @@ func TestAssert(t *testing.T) {
 	assert.IsNil(nil)
 	assert.IsNotNil("abc")
 
+	var valA int = 1
+	var valB int64 = 1
+	assert.NotEqual(valA, valB)
+	assert.EqualValues(valA, valB)
+
+	assert.ShouldBeFalse(false)
+	assert.ShouldBeTrue(true)
 }

maputil/map.go

@@ -5,6 +5,7 @@
 package maputil
 
 import (
+	"fmt"
 	"reflect"
 
 	"github.com/duke-git/lancet/v2/slice"
@@ -303,3 +304,83 @@ func HasKey[K comparable, V any](m map[K]V, key K) bool {
 	_, haskey := m[key]
 	return haskey
 }
+
+// MapToStruct converts map to struct
+// Play: todo
+func MapToStruct(m map[string]any, structObj any) error {
+	for k, v := range m {
+		err := setStructField(structObj, k, v)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func setStructField(structObj any, fieldName string, fieldValue any) error {
+	structVal := reflect.ValueOf(structObj).Elem()
+
+	fName := getFieldNameByJsonTag(structObj, fieldName)
+	if fName == "" {
+		return fmt.Errorf("Struct field json tag don't match map key : %s in obj", fieldName)
+	}
+
+	fieldVal := structVal.FieldByName(fName)
+
+	if !fieldVal.IsValid() {
+		return fmt.Errorf("No such field: %s in obj", fieldName)
+	}
+
+	if !fieldVal.CanSet() {
+		return fmt.Errorf("Cannot set %s field value", fieldName)
+	}
+
+	val := reflect.ValueOf(fieldValue)
+
+	if fieldVal.Type() != val.Type() {
+
+		if val.CanConvert(fieldVal.Type()) {
+			fieldVal.Set(val.Convert(fieldVal.Type()))
+			return nil
+		}
+
+		if m, ok := fieldValue.(map[string]any); ok {
+
+			if fieldVal.Kind() == reflect.Struct {
+				return MapToStruct(m, fieldVal.Addr().Interface())
+			}
+
+			if fieldVal.Kind() == reflect.Ptr && fieldVal.Type().Elem().Kind() == reflect.Struct {
+				if fieldVal.IsNil() {
+					fieldVal.Set(reflect.New(fieldVal.Type().Elem()))
+				}
+
+				return MapToStruct(m, fieldVal.Interface())
+			}
+
+		}
+
+		return fmt.Errorf("Map value type don't match struct field type")
+	}
+
+	fieldVal.Set(val)
+
+	return nil
+}
+
+func getFieldNameByJsonTag(structObj any, jsonTag string) string {
+	s := reflect.TypeOf(structObj).Elem()
+
+	for i := 0; i < s.NumField(); i++ {
+		field := s.Field(i)
+		tag := field.Tag
+		name := tag.Get("json")
+
+		if name == jsonTag {
+			return field.Name
+		}
+	}
+
+	return ""
+}

maputil/map_test.go

@@ -472,3 +472,42 @@ func TestHasKey(t *testing.T) {
 	assert.Equal(true, HasKey(m, "a"))
 	assert.Equal(false, HasKey(m, "c"))
 }
+
+func TestMapToStruct(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestMapToStruct")
+
+	type (
+		Person struct {
+			Name  string   `json:"name"`
+			Age   int      `json:"age"`
+			Phone string   `json:"phone"`
+			Addr  *Address `json:"address"`
+		}
+
+		Address struct {
+			Street string `json:"street"`
+			Number int    `json:"number"`
+		}
+	)
+
+	m := map[string]interface{}{
+		"name":  "Nothin",
+		"age":   28,
+		"phone": "123456789",
+		"address": map[string]interface{}{
+			"street": "test",
+			"number": 1,
+		},
+	}
+
+	var p Person
+	err := MapToStruct(m, &p)
+	assert.IsNil(err)
+	assert.Equal(m["name"], p.Name)
+	assert.Equal(m["age"], p.Age)
+	assert.Equal(m["phone"], p.Phone)
+	assert.Equal("test", p.Addr.Street)
+	assert.Equal(1, p.Addr.Number)
+}

maputil/typemap.go

@@ -62,18 +62,25 @@ var _ = func() struct{} {
 */
 // Play: https://go.dev/play/p/4K7KBEPgS5M
 func MapTo(src any, dst any) error {
-
 	dstRef := reflect.ValueOf(dst)
+
 	if dstRef.Kind() != reflect.Ptr {
 		return fmt.Errorf("dst is not ptr")
 	}
 
+	dstElem := dstRef.Type().Elem()
+	if dstElem.Kind() == reflect.Struct {
+		srcMap := src.(map[string]interface{})
+		return MapToStruct(srcMap, dst)
+	}
+
 	dstRef = reflect.Indirect(dstRef)
 
 	srcRef := reflect.ValueOf(src)
 	if srcRef.Kind() == reflect.Ptr || srcRef.Kind() == reflect.Interface {
 		srcRef = srcRef.Elem()
 	}
+
 	if f, ok := mapHandlers[srcRef.Kind()]; ok {
 		return f(srcRef, dstRef)
 	}
@@ -121,7 +128,7 @@ func convertSlice(src reflect.Value, dst reflect.Value) error {
 
 func convertMap(src reflect.Value, dst reflect.Value) error {
 	if src.Kind() != reflect.Map || dst.Kind() != reflect.Struct {
-		if src.Kind() == reflect.Interface {
+		if src.Kind() == reflect.Interface && dst.IsValid() {
 			return convertMap(src.Elem(), dst)
 		} else {
 			return fmt.Errorf("src or dst type error,%s,%s", src.Type().String(), dst.Type().String())
@@ -129,7 +136,9 @@ func convertMap(src reflect.Value, dst reflect.Value) error {
 	}
 	dstType := dst.Type()
 	num := dstType.NumField()
+
 	exist := map[string]int{}
+
 	for i := 0; i < num; i++ {
 		k := dstType.Field(i).Tag.Get("json")
 		if k == "" {
@@ -138,7 +147,6 @@ func convertMap(src reflect.Value, dst reflect.Value) error {
 		if strings.Contains(k, ",") {
 			taglist := strings.Split(k, ",")
 			if taglist[0] == "" {
-
 				k = dstType.Field(i).Name
 			} else {
 				k = taglist[0]
@@ -150,9 +158,11 @@ func convertMap(src reflect.Value, dst reflect.Value) error {
 	}
 
 	keys := src.MapKeys()
+
 	for _, key := range keys {
 		if index, ok := exist[key.String()]; ok {
 			v := dst.Field(index)
+
 			if v.Kind() == reflect.Struct {
 				err := convertMap(src.MapIndex(key), v)
 				if err != nil {

maputil/typemap_test.go

@@ -8,10 +8,10 @@ import (
 
 type (
 	Person struct {
-		Name  string  `json:"name"`
-		Age   int     `json:"age"`
-		Phone string  `json:"phone"`
-		Addr  Address `json:"address"`
+		Name    string   `json:"name"`
+		Age     int      `json:"age"`
+		Phone   string   `json:"phone"`
+		Address *Address `json:"address"`
 	}
 
 	Address struct {
@@ -38,11 +38,12 @@ func TestStructType(t *testing.T) {
 	var p Person
 	err := MapTo(src, &p)
 	assert.IsNil(err)
+
 	assert.Equal(src["name"], p.Name)
 	assert.Equal(src["age"], p.Age)
 	assert.Equal(src["phone"], p.Phone)
-	assert.Equal("test", p.Addr.Street)
-	assert.Equal(1, p.Addr.Number)
+	assert.Equal("test", p.Address.Street)
+	assert.Equal(1, p.Address.Number)
 }
 
 func TestBaseType(t *testing.T) {

retry/retry.go

@@ -8,6 +8,8 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"math"
+	"math/rand"
 	"reflect"
 	"runtime"
 	"strings"
@@ -18,14 +20,14 @@ const (
 	// DefaultRetryTimes times of retry
 	DefaultRetryTimes = 5
 	// DefaultRetryDuration time duration of two retries
-	DefaultRetryDuration = time.Second * 3
+	DefaultRetryLinearInterval = time.Second * 3
 )
 
 // RetryConfig is config for retry
 type RetryConfig struct {
-	context       context.Context
-	retryTimes    uint
-	retryDuration time.Duration
+	context         context.Context
+	retryTimes      uint
+	backoffStrategy BackoffStrategy
 }
 
 // RetryFunc is function that retry executes
@@ -42,11 +44,59 @@ func RetryTimes(n uint) Option {
 	}
 }
 
-// RetryDuration set duration of retries.
-// Play: https://go.dev/play/p/nk2XRmagfVF
-func RetryDuration(d time.Duration) Option {
+// RetryWithCustomBackoff set abitary custom backoff strategy
+// todo: Add playground link
+func RetryWithCustomBackoff(backoffStrategy BackoffStrategy) Option {
+	if backoffStrategy == nil {
+		panic("programming error: backoffStrategy must be not nil")
+	}
+
 	return func(rc *RetryConfig) {
-		rc.retryDuration = d
+		rc.backoffStrategy = backoffStrategy
+	}
+}
+
+// RetryWithLinearBackoff set linear strategy backoff
+// todo: Add playground link
+func RetryWithLinearBackoff(interval time.Duration) Option {
+	if interval <= 0 {
+		panic("programming error: retry interval should not be lower or equal to 0")
+	}
+
+	return func(rc *RetryConfig) {
+		rc.backoffStrategy = &linear{
+			interval: interval,
+		}
+	}
+}
+
+// RetryWithExponentialWithJitterBackoff set exponential strategy backoff
+// todo: Add playground link
+func RetryWithExponentialWithJitterBackoff(interval time.Duration, base uint64, maxJitter time.Duration) Option {
+	if interval <= 0 {
+		panic("programming error: retry interval should not be lower or equal to 0")
+	}
+
+	if maxJitter < 0 {
+		panic("programming error: retry maxJitter should not be lower to 0")
+	}
+
+	if base%2 == 0 {
+		return func(rc *RetryConfig) {
+			rc.backoffStrategy = &shiftExponentialWithJitter{
+				interval:  interval,
+				maxJitter: maxJitter,
+				shifter:   uint64(math.Log2(float64(base))),
+			}
+		}
+	}
+
+	return func(rc *RetryConfig) {
+		rc.backoffStrategy = &exponentialWithJitter{
+			interval:  interval,
+			base:      time.Duration(base),
+			maxJitter: maxJitter,
+		}
 	}
 }
 
@@ -63,21 +113,26 @@ func Context(ctx context.Context) Option {
 // Play: https://go.dev/play/p/nk2XRmagfVF
 func Retry(retryFunc RetryFunc, opts ...Option) error {
 	config := &RetryConfig{
-		retryTimes:    DefaultRetryTimes,
-		retryDuration: DefaultRetryDuration,
-		context:       context.TODO(),
+		retryTimes: DefaultRetryTimes,
+		context:    context.TODO(),
 	}
 
 	for _, opt := range opts {
 		opt(config)
 	}
 
+	if config.backoffStrategy == nil {
+		config.backoffStrategy = &linear{
+			interval: DefaultRetryLinearInterval,
+		}
+	}
+
 	var i uint
 	for i < config.retryTimes {
 		err := retryFunc()
 		if err != nil {
 			select {
-			case <-time.After(config.retryDuration):
+			case <-time.After(config.backoffStrategy.CalculateInterval()):
 			case <-config.context.Done():
 				return errors.New("retry is cancelled")
 			}
@@ -93,3 +148,58 @@ func Retry(retryFunc RetryFunc, opts ...Option) error {
 
 	return fmt.Errorf("function %s run failed after %d times retry", funcName, i)
 }
+
+// BackoffStrategy is an interface that defines a method for calculating backoff intervals.
+type BackoffStrategy interface {
+	// CalculateInterval returns the time.Duration after which the next retry attempt should be made.
+	CalculateInterval() time.Duration
+}
+
+// linear is a struct that implements the BackoffStrategy interface using a linear backoff strategy.
+type linear struct {
+	// interval specifies the fixed duration to wait between retry attempts.
+	interval time.Duration
+}
+
+// CalculateInterval calculates the next interval returns a constant.
+func (l *linear) CalculateInterval() time.Duration {
+	return l.interval
+}
+
+// exponentialWithJitter is a struct that implements the BackoffStrategy interface using a exponential backoff strategy.
+type exponentialWithJitter struct {
+	base      time.Duration // base is the multiplier for the exponential backoff.
+	interval  time.Duration // interval is the current backoff interval, which will be adjusted over time.
+	maxJitter time.Duration // maxJitter is the maximum amount of jitter to apply to the backoff interval.
+}
+
+// CalculateInterval calculates the next backoff interval with jitter and updates the interval.
+func (e *exponentialWithJitter) CalculateInterval() time.Duration {
+	current := e.interval
+	e.interval = e.interval * e.base
+	return current + jitter(e.maxJitter)
+}
+
+// shiftExponentialWithJitter is a struct that implements the BackoffStrategy interface using a exponential backoff strategy.
+type shiftExponentialWithJitter struct {
+	interval  time.Duration // interval is the current backoff interval, which will be adjusted over time.
+	maxJitter time.Duration // maxJitter is the maximum amount of jitter to apply to the backoff interval.
+	shifter   uint64        // shift by n faster than multiplication
+}
+
+// CalculateInterval calculates the next backoff interval with jitter and updates the interval.
+// Uses shift instead of multiplication
+func (e *shiftExponentialWithJitter) CalculateInterval() time.Duration {
+	current := e.interval
+	e.interval = e.interval << e.shifter
+	return current + jitter(e.maxJitter)
+}
+
+// Jitter adds a random duration, up to maxJitter,
+// to the current interval to introduce randomness and avoid synchronized patterns in retry behavior
+func jitter(maxJitter time.Duration) time.Duration {
+	if maxJitter == 0 {
+		return 0
+	}
+	return time.Duration(rand.Int63n(int64(maxJitter)) + 1)
+}

retry/retry_example_test.go

@@ -20,7 +20,7 @@ func ExampleContext() {
 	}
 
 	Retry(increaseNumber,
-		RetryDuration(time.Microsecond*50),
+		RetryWithLinearBackoff(time.Microsecond*50),
 		Context(ctx),
 	)
 
@@ -30,7 +30,7 @@ func ExampleContext() {
 	// 4
 }
 
-func ExampleRetryDuration() {
+func ExampleRetryWithLinearBackoff() {
 	number := 0
 	increaseNumber := func() error {
 		number++
@@ -40,7 +40,57 @@ func ExampleRetryDuration() {
 		return errors.New("error occurs")
 	}
 
-	err := Retry(increaseNumber, RetryDuration(time.Microsecond*50))
+	err := Retry(increaseNumber, RetryWithLinearBackoff(time.Microsecond*50))
+	if err != nil {
+		return
+	}
+
+	fmt.Println(number)
+
+	// Output:
+	// 3
+}
+
+type ExampleCustomBackoffStrategy struct {
+	interval time.Duration
+}
+
+func (c *ExampleCustomBackoffStrategy) CalculateInterval() time.Duration {
+	return c.interval + 1
+}
+
+func ExampleRetryWithCustomBackoff() {
+	number := 0
+	increaseNumber := func() error {
+		number++
+		if number == 3 {
+			return nil
+		}
+		return errors.New("error occurs")
+	}
+
+	err := Retry(increaseNumber, RetryWithCustomBackoff(&ExampleCustomBackoffStrategy{interval: time.Microsecond * 50}))
+	if err != nil {
+		return
+	}
+
+	fmt.Println(number)
+
+	// Output:
+	// 3
+}
+
+func ExampleRetryWithExponentialWithJitterBackoff() {
+	number := 0
+	increaseNumber := func() error {
+		number++
+		if number == 3 {
+			return nil
+		}
+		return errors.New("error occurs")
+	}
+
+	err := Retry(increaseNumber, RetryWithExponentialWithJitterBackoff(time.Microsecond*50, 2, time.Microsecond*25))
 	if err != nil {
 		return
 	}
@@ -81,7 +131,7 @@ func ExampleRetry() {
 		return errors.New("error occurs")
 	}
 
-	err := Retry(increaseNumber, RetryDuration(time.Microsecond*50))
+	err := Retry(increaseNumber, RetryWithLinearBackoff(time.Microsecond*50))
 	if err != nil {
 		return
 	}

retry/retry_test.go

@@ -20,12 +20,86 @@ func TestRetryFailed(t *testing.T) {
 		return errors.New("error occurs")
 	}
 
-	err := Retry(increaseNumber, RetryDuration(time.Microsecond*50))
+	err := Retry(increaseNumber, RetryWithLinearBackoff(time.Microsecond*50))
 
 	assert.IsNotNil(err)
 	assert.Equal(DefaultRetryTimes, number)
 }
 
+func TestRetryShiftExponentialWithJitterFailed(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestRetryShiftExponentialWithJitterFailed")
+
+	var number int
+	increaseNumber := func() error {
+		number++
+		return errors.New("error occurs")
+	}
+
+	err := Retry(increaseNumber, RetryWithExponentialWithJitterBackoff(time.Microsecond*50, 2, time.Microsecond*25))
+
+	assert.IsNotNil(err)
+	assert.Equal(DefaultRetryTimes, number)
+}
+
+func TestRetryExponentialWithJitterFailed(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestRetryExponentialWithJitterFailed")
+
+	var number int
+	increaseNumber := func() error {
+		number++
+		return errors.New("error occurs")
+	}
+
+	err := Retry(increaseNumber, RetryWithExponentialWithJitterBackoff(time.Microsecond*50, 3, time.Microsecond*25))
+
+	assert.IsNotNil(err)
+	assert.Equal(DefaultRetryTimes, number)
+}
+
+func TestRetryWithExponentialSucceeded(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestRetryWithExponentialSucceeded")
+
+	var number int
+	increaseNumber := func() error {
+		number++
+		if number == DefaultRetryTimes {
+			return nil
+		}
+		return errors.New("error occurs")
+	}
+
+	err := Retry(increaseNumber, RetryWithExponentialWithJitterBackoff(time.Microsecond*50, 3, time.Microsecond*25))
+
+	assert.IsNil(err)
+	assert.Equal(DefaultRetryTimes, number)
+}
+
+func TestRetryWithExponentialShiftSucceeded(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestRetryWithExponentialShiftSucceeded")
+
+	var number int
+	increaseNumber := func() error {
+		number++
+		if number == DefaultRetryTimes {
+			return nil
+		}
+		return errors.New("error occurs")
+	}
+
+	err := Retry(increaseNumber, RetryWithExponentialWithJitterBackoff(time.Microsecond*50, 4, time.Microsecond*25))
+
+	assert.IsNil(err)
+	assert.Equal(DefaultRetryTimes, number)
+}
+
 func TestRetrySucceeded(t *testing.T) {
 	t.Parallel()
 
@@ -40,12 +114,108 @@ func TestRetrySucceeded(t *testing.T) {
 		return errors.New("error occurs")
 	}
 
-	err := Retry(increaseNumber, RetryDuration(time.Microsecond*50))
+	err := Retry(increaseNumber, RetryWithLinearBackoff(time.Microsecond*50))
 
 	assert.IsNil(err)
 	assert.Equal(DefaultRetryTimes, number)
 }
 
+func TestRetryOneShotSucceeded(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestRetryOneShotSucceeded")
+
+	var number int
+	increaseNumber := func() error {
+		number++
+		return nil
+	}
+
+	err := Retry(increaseNumber, RetryWithLinearBackoff(time.Microsecond*50))
+
+	assert.IsNil(err)
+	assert.Equal(1, number)
+}
+
+func TestRetryWitCustomBackoffOneShotSucceeded(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestRetryWitCustomBackoffOneShotSucceeded")
+
+	var number int
+	increaseNumber := func() error {
+		number++
+		if number == DefaultRetryTimes {
+			return nil
+		}
+		return errors.New("error occurs")
+	}
+
+	err := Retry(increaseNumber, RetryWithCustomBackoff(&TestCustomBackoffStrategy{interval: time.Microsecond * 50}))
+
+	assert.IsNil(err)
+	assert.Equal(5, number)
+}
+
+type TestCustomBackoffStrategy struct {
+	interval time.Duration
+}
+
+func (c *TestCustomBackoffStrategy) CalculateInterval() time.Duration {
+	return c.interval + 1
+}
+
+func TestRetryWithExponentialWithJitterBackoffShiftOneShotSucceeded(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestRetryWithExponentialWithJitterBackoffShiftOneShotSucceeded")
+
+	var number int
+	increaseNumber := func() error {
+		number++
+		return nil
+	}
+
+	err := Retry(increaseNumber, RetryWithExponentialWithJitterBackoff(time.Microsecond*50, 2, time.Microsecond*25))
+
+	assert.IsNil(err)
+	assert.Equal(1, number)
+}
+
+func TestRetryWithExponentialWithJitterBackoffOneShotSucceeded(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestRetryWithExponentialWithJitterBackoffOneShotSucceeded")
+
+	var number int
+	increaseNumber := func() error {
+		number++
+		return nil
+	}
+
+	err := Retry(increaseNumber, RetryWithExponentialWithJitterBackoff(time.Microsecond*50, 3, time.Microsecond*25))
+
+	assert.IsNil(err)
+	assert.Equal(1, number)
+}
+
+func TestRetryWithExponentialWithJitterBackoffNoJitterOneShotSucceeded(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestRetryWithExponentialWithJitterBackoffNoJitterOneShotSucceeded")
+
+	var number int
+	increaseNumber := func() error {
+		number++
+		return nil
+	}
+
+	err := Retry(increaseNumber, RetryWithExponentialWithJitterBackoff(time.Microsecond*50, 3, 0))
+
+	assert.IsNil(err)
+	assert.Equal(1, number)
+}
+
 func TestSetRetryTimes(t *testing.T) {
 	t.Parallel()
 
@@ -57,7 +227,7 @@ func TestSetRetryTimes(t *testing.T) {
 		return errors.New("error occurs")
 	}
 
-	err := Retry(increaseNumber, RetryDuration(time.Microsecond*50), RetryTimes(3))
+	err := Retry(increaseNumber, RetryWithLinearBackoff(time.Microsecond*50), RetryTimes(3))
 
 	assert.IsNotNil(err)
 	assert.Equal(3, number)
@@ -79,7 +249,7 @@ func TestCancelRetry(t *testing.T) {
 	}
 
 	err := Retry(increaseNumber,
-		RetryDuration(time.Microsecond*50),
+		RetryWithLinearBackoff(time.Microsecond*50),
 		Context(ctx),
 	)
 

slice/slice.go

@@ -619,7 +619,7 @@ func IntSlice(slice any) []int {
 }
 
 // DeleteAt delete the element of slice at index.
-// Play: https://go.dev/play/p/pJ-d6MUWcvK
+// Play: https://go.dev/play/p/800B1dPBYyd
 func DeleteAt[T any](slice []T, index int) []T {
 	if index >= len(slice) {
 		index = len(slice) - 1
@@ -633,7 +633,7 @@ func DeleteAt[T any](slice []T, index int) []T {
 }
 
 // DeleteRange delete the element of slice from start index to end index（exclude).
-// Play: todo
+// Play: https://go.dev/play/p/945HwiNrnle
 func DeleteRange[T any](slice []T, start, end int) []T {
 	result := make([]T, 0, len(slice)-(end-start))
 

stream/stream.go

@@ -47,19 +47,19 @@ import (
 // 	Concat(streams ...StreamI[T]) StreamI[T]
 // }
 
-type stream[T any] struct {
+type Stream[T any] struct {
 	source []T
 }
 
 // Of creates a stream whose elements are the specified values.
 // Play: https://go.dev/play/p/jI6_iZZuVFE
-func Of[T any](elems ...T) stream[T] {
+func Of[T any](elems ...T) Stream[T] {
 	return FromSlice(elems)
 }
 
 // Generate stream where each element is generated by the provided generater function
 // Play: https://go.dev/play/p/rkOWL1yA3j9
-func Generate[T any](generator func() func() (item T, ok bool)) stream[T] {
+func Generate[T any](generator func() func() (item T, ok bool)) Stream[T] {
 	source := make([]T, 0)
 
 	var zeroValue T
@@ -76,13 +76,13 @@ func Generate[T any](generator func() func() (item T, ok bool)) stream[T] {
 
 // FromSlice creates stream from slice.
 // Play: https://go.dev/play/p/wywTO0XZtI4
-func FromSlice[T any](source []T) stream[T] {
-	return stream[T]{source: source}
+func FromSlice[T any](source []T) Stream[T] {
+	return Stream[T]{source: source}
 }
 
 // FromChannel creates stream from channel.
 // Play: https://go.dev/play/p/9TZYugGMhXZ
-func FromChannel[T any](source <-chan T) stream[T] {
+func FromChannel[T any](source <-chan T) Stream[T] {
 	s := make([]T, 0)
 
 	for v := range source {
@@ -94,7 +94,7 @@ func FromChannel[T any](source <-chan T) stream[T] {
 
 // FromRange creates a number stream from start to end. both start and end are included. [start, end]
 // Play: https://go.dev/play/p/9Ex1-zcg-B-
-func FromRange[T constraints.Integer | constraints.Float](start, end, step T) stream[T] {
+func FromRange[T constraints.Integer | constraints.Float](start, end, step T) Stream[T] {
 	if end < start {
 		panic("stream.FromRange: param start should be before param end")
 	} else if step <= 0 {
@@ -113,7 +113,7 @@ func FromRange[T constraints.Integer | constraints.Float](start, end, step T) st
 
 // Concat creates a lazily concatenated stream whose elements are all the elements of the first stream followed by all the elements of the second stream.
 // Play: https://go.dev/play/p/HM4OlYk_OUC
-func Concat[T any](a, b stream[T]) stream[T] {
+func Concat[T any](a, b Stream[T]) Stream[T] {
 	source := make([]T, 0)
 
 	source = append(source, a.source...)
@@ -124,7 +124,7 @@ func Concat[T any](a, b stream[T]) stream[T] {
 
 // Distinct returns a stream that removes the duplicated items.
 // Play: https://go.dev/play/p/eGkOSrm64cB
-func (s stream[T]) Distinct() stream[T] {
+func (s Stream[T]) Distinct() Stream[T] {
 	source := make([]T, 0)
 
 	distinct := map[string]bool{}
@@ -153,7 +153,7 @@ func hashKey(data any) string {
 
 // Filter returns a stream consisting of the elements of this stream that match the given predicate.
 // Play: https://go.dev/play/p/MFlSANo-buc
-func (s stream[T]) Filter(predicate func(item T) bool) stream[T] {
+func (s Stream[T]) Filter(predicate func(item T) bool) Stream[T] {
 	source := make([]T, 0)
 
 	for _, v := range s.source {
@@ -167,7 +167,7 @@ func (s stream[T]) Filter(predicate func(item T) bool) stream[T] {
 
 // Map returns a stream consisting of the elements of this stream that apply the given function to elements of stream.
 // Play: https://go.dev/play/p/OtNQUImdYko
-func (s stream[T]) Map(mapper func(item T) T) stream[T] {
+func (s Stream[T]) Map(mapper func(item T) T) Stream[T] {
 	source := make([]T, s.Count())
 
 	for i, v := range s.source {
@@ -179,7 +179,7 @@ func (s stream[T]) Map(mapper func(item T) T) stream[T] {
 
 // Peek returns a stream consisting of the elements of this stream, additionally performing the provided action on each element as elements are consumed from the resulting stream.
 // Play: https://go.dev/play/p/u1VNzHs6cb2
-func (s stream[T]) Peek(consumer func(item T)) stream[T] {
+func (s Stream[T]) Peek(consumer func(item T)) Stream[T] {
 	for _, v := range s.source {
 		consumer(v)
 	}
@@ -190,7 +190,7 @@ func (s stream[T]) Peek(consumer func(item T)) stream[T] {
 // Skip returns a stream consisting of the remaining elements of this stream after discarding the first n elements of the stream.
 // If this stream contains fewer than n elements then an empty stream will be returned.
 // Play: https://go.dev/play/p/fNdHbqjahum
-func (s stream[T]) Skip(n int) stream[T] {
+func (s Stream[T]) Skip(n int) Stream[T] {
 	if n <= 0 {
 		return s
 	}
@@ -211,7 +211,7 @@ func (s stream[T]) Skip(n int) stream[T] {
 
 // Limit returns a stream consisting of the elements of this stream, truncated to be no longer than maxSize in length.
 // Play: https://go.dev/play/p/qsO4aniDcGf
-func (s stream[T]) Limit(maxSize int) stream[T] {
+func (s Stream[T]) Limit(maxSize int) Stream[T] {
 	if s.source == nil {
 		return s
 	}
@@ -231,7 +231,7 @@ func (s stream[T]) Limit(maxSize int) stream[T] {
 
 // AllMatch returns whether all elements of this stream match the provided predicate.
 // Play: https://go.dev/play/p/V5TBpVRs-Cx
-func (s stream[T]) AllMatch(predicate func(item T) bool) bool {
+func (s Stream[T]) AllMatch(predicate func(item T) bool) bool {
 	for _, v := range s.source {
 		if !predicate(v) {
 			return false
@@ -243,7 +243,7 @@ func (s stream[T]) AllMatch(predicate func(item T) bool) bool {
 
 // AnyMatch returns whether any elements of this stream match the provided predicate.
 // Play: https://go.dev/play/p/PTCnWn4OxSn
-func (s stream[T]) AnyMatch(predicate func(item T) bool) bool {
+func (s Stream[T]) AnyMatch(predicate func(item T) bool) bool {
 	for _, v := range s.source {
 		if predicate(v) {
 			return true
@@ -255,13 +255,13 @@ func (s stream[T]) AnyMatch(predicate func(item T) bool) bool {
 
 // NoneMatch returns whether no elements of this stream match the provided predicate.
 // Play: https://go.dev/play/p/iWS64pL1oo3
-func (s stream[T]) NoneMatch(predicate func(item T) bool) bool {
+func (s Stream[T]) NoneMatch(predicate func(item T) bool) bool {
 	return !s.AnyMatch(predicate)
 }
 
 // ForEach performs an action for each element of this stream.
 // Play: https://go.dev/play/p/Dsm0fPqcidk
-func (s stream[T]) ForEach(action func(item T)) {
+func (s Stream[T]) ForEach(action func(item T)) {
 	for _, v := range s.source {
 		action(v)
 	}
@@ -269,7 +269,7 @@ func (s stream[T]) ForEach(action func(item T)) {
 
 // Reduce performs a reduction on the elements of this stream, using an associative accumulation function, and returns an Optional describing the reduced value, if any.
 // Play: https://go.dev/play/p/6uzZjq_DJLU
-func (s stream[T]) Reduce(initial T, accumulator func(a, b T) T) T {
+func (s Stream[T]) Reduce(initial T, accumulator func(a, b T) T) T {
 	for _, v := range s.source {
 		initial = accumulator(initial, v)
 	}
@@ -279,13 +279,13 @@ func (s stream[T]) Reduce(initial T, accumulator func(a, b T) T) T {
 
 // Count returns the count of elements in the stream.
 // Play: https://go.dev/play/p/r3koY6y_Xo-
-func (s stream[T]) Count() int {
+func (s Stream[T]) Count() int {
 	return len(s.source)
 }
 
 // FindFirst returns the first element of this stream and true, or zero value and false if the stream is empty.
 // Play: https://go.dev/play/p/9xEf0-6C1e3
-func (s stream[T]) FindFirst() (T, bool) {
+func (s Stream[T]) FindFirst() (T, bool) {
 	var result T
 
 	if s.source == nil || len(s.source) == 0 {
@@ -297,7 +297,7 @@ func (s stream[T]) FindFirst() (T, bool) {
 
 // FindLast returns the last element of this stream and true, or zero value and false if the stream is empty.
 // Play: https://go.dev/play/p/WZD2rDAW-2h
-func (s stream[T]) FindLast() (T, bool) {
+func (s Stream[T]) FindLast() (T, bool) {
 	var result T
 
 	if s.source == nil || len(s.source) == 0 {
@@ -309,7 +309,7 @@ func (s stream[T]) FindLast() (T, bool) {
 
 // Reverse returns a stream whose elements are reverse order of given stream.
 // Play: https://go.dev/play/p/A8_zkJnLHm4
-func (s stream[T]) Reverse() stream[T] {
+func (s Stream[T]) Reverse() Stream[T] {
 	l := len(s.source)
 	source := make([]T, l)
 
@@ -321,7 +321,7 @@ func (s stream[T]) Reverse() stream[T] {
 
 // Range returns a stream whose elements are in the range from start(included) to end(excluded) original stream.
 // Play: https://go.dev/play/p/indZY5V2f4j
-func (s stream[T]) Range(start, end int) stream[T] {
+func (s Stream[T]) Range(start, end int) Stream[T] {
 	if start < 0 {
 		start = 0
 	}
@@ -347,7 +347,7 @@ func (s stream[T]) Range(start, end int) stream[T] {
 
 // Sorted returns a stream consisting of the elements of this stream, sorted according to the provided less function.
 // Play: https://go.dev/play/p/XXtng5uonFj
-func (s stream[T]) Sorted(less func(a, b T) bool) stream[T] {
+func (s Stream[T]) Sorted(less func(a, b T) bool) Stream[T] {
 	source := []T{}
 	source = append(source, s.source...)
 
@@ -359,7 +359,7 @@ func (s stream[T]) Sorted(less func(a, b T) bool) stream[T] {
 // Max returns the maximum element of this stream according to the provided less function.
 // less: a > b
 // Play: https://go.dev/play/p/fm-1KOPtGzn
-func (s stream[T]) Max(less func(a, b T) bool) (T, bool) {
+func (s Stream[T]) Max(less func(a, b T) bool) (T, bool) {
 	var max T
 
 	if len(s.source) == 0 {
@@ -377,7 +377,7 @@ func (s stream[T]) Max(less func(a, b T) bool) (T, bool) {
 // Min returns the minimum element of this stream according to the provided less function.
 // less: a < b
 // Play: https://go.dev/play/p/vZfIDgGNRe_0
-func (s stream[T]) Min(less func(a, b T) bool) (T, bool) {
+func (s Stream[T]) Min(less func(a, b T) bool) (T, bool) {
 	var min T
 
 	if len(s.source) == 0 {
@@ -395,6 +395,6 @@ func (s stream[T]) Min(less func(a, b T) bool) (T, bool) {
 
 // ToSlice return the elements in the stream.
 // Play: https://go.dev/play/p/jI6_iZZuVFE
-func (s stream[T]) ToSlice() []T {
+func (s Stream[T]) ToSlice() []T {
 	return s.source
 }

strutil/string.go

@@ -121,40 +121,48 @@ func UpperSnakeCase(s string) string {
 // Before returns the substring of the source string up to the first occurrence of the specified string.
 // Play: https://go.dev/play/p/JAWTZDS4F5w
 func Before(s, char string) string {
-	if s == "" || char == "" {
+	i := strings.Index(s, char)
+
+	if s == "" || char == "" || i == -1 {
 		return s
 	}
-	i := strings.Index(s, char)
+
 	return s[0:i]
 }
 
 // BeforeLast returns the substring of the source string up to the last occurrence of the specified string.
 // Play: https://go.dev/play/p/pJfXXAoG_Te
 func BeforeLast(s, char string) string {
-	if s == "" || char == "" {
+	i := strings.LastIndex(s, char)
+
+	if s == "" || char == "" || i == -1 {
 		return s
 	}
-	i := strings.LastIndex(s, char)
+
 	return s[0:i]
 }
 
 // After returns the substring after the first occurrence of a specified string in the source string.
 // Play: https://go.dev/play/p/RbCOQqCDA7m
 func After(s, char string) string {
-	if s == "" || char == "" {
+	i := strings.Index(s, char)
+
+	if s == "" || char == "" || i == -1 {
 		return s
 	}
-	i := strings.Index(s, char)
+
 	return s[i+len(char):]
 }
 
 // AfterLast returns the substring after the last occurrence of a specified string in the source string.
 // Play: https://go.dev/play/p/1TegARrb8Yn
 func AfterLast(s, char string) string {
-	if s == "" || char == "" {
+	i := strings.LastIndex(s, char)
+
+	if s == "" || char == "" || i == -1 {
 		return s
 	}
-	i := strings.LastIndex(s, char)
+
 	return s[i+len(char):]
 }
 
@@ -574,3 +582,15 @@ func RemoveWhiteSpace(str string, repalceAll bool) string {
 
 	return strings.TrimSpace(str)
 }
+
+// SubInBetween return substring between the start and end position(excluded) of source string.
+// Play: todo
+func SubInBetween(str string, start string, end string) string {
+	if _, after, ok := strings.Cut(str, start); ok {
+		if before, _, ok := strings.Cut(after, end); ok {
+			return before
+		}
+	}
+
+	return ""
+}

strutil/string_example_test.go

@@ -653,3 +653,17 @@ func ExampleRemoveWhiteSpace() {
 	// helloworld
 	// hello world
 }
+
+func ExampleSubInBetween() {
+	str := "abcde"
+
+	result1 := SubInBetween(str, "", "de")
+	result2 := SubInBetween(str, "a", "d")
+
+	fmt.Println(result1)
+	fmt.Println(result2)
+
+	// Output:
+	// abc
+	// bc
+}

strutil/string_test.go

@@ -230,6 +230,8 @@ func TestBefore(t *testing.T) {
 
 	assert.Equal("lancet", Before("lancet", ""))
 	assert.Equal("", Before("lancet", "lancet"))
+	assert.Equal("lancet", Before("lancet", "abcdef"))
+
 	assert.Equal("github.com", Before("github.com/test/lancet", "/"))
 	assert.Equal("github.com/", Before("github.com/test/lancet", "test"))
 }
@@ -240,10 +242,10 @@ func TestBeforeLast(t *testing.T) {
 	assert := internal.NewAssert(t, "TestBeforeLast")
 
 	assert.Equal("lancet", BeforeLast("lancet", ""))
+	assert.Equal("lancet", BeforeLast("lancet", "abcdef"))
+
 	assert.Equal("github.com/test", BeforeLast("github.com/test/lancet", "/"))
 	assert.Equal("github.com/test/", BeforeLast("github.com/test/test/lancet", "test"))
-
-	assert.NotEqual("github.com/", BeforeLast("github.com/test/test/lancet", "test"))
 }
 
 func TestAfter(t *testing.T) {
@@ -255,6 +257,8 @@ func TestAfter(t *testing.T) {
 	assert.Equal("", After("lancet", "lancet"))
 	assert.Equal("test/lancet", After("github.com/test/lancet", "/"))
 	assert.Equal("/lancet", After("github.com/test/lancet", "test"))
+
+	assert.Equal("lancet", After("lancet", "abcdef"))
 }
 
 func TestAfterLast(t *testing.T) {
@@ -266,8 +270,7 @@ func TestAfterLast(t *testing.T) {
 	assert.Equal("lancet", AfterLast("github.com/test/lancet", "/"))
 	assert.Equal("/lancet", AfterLast("github.com/test/lancet", "test"))
 	assert.Equal("/lancet", AfterLast("github.com/test/test/lancet", "test"))
-
-	assert.NotEqual("/test/lancet", AfterLast("github.com/test/test/lancet", "test"))
+	assert.Equal("lancet", AfterLast("lancet", "abcdef"))
 }
 
 func TestIsString(t *testing.T) {
@@ -566,3 +569,15 @@ func TestRemoveWhiteSpace(t *testing.T) {
 	assert.Equal("helloworld", RemoveWhiteSpace(str, true))
 	assert.Equal("hello world", RemoveWhiteSpace(str, false))
 }
+
+func TestSubInBetween(t *testing.T) {
+	assert := internal.NewAssert(t, "TestSubInBetween")
+
+	str := "abcde"
+
+	assert.Equal("", SubInBetween(str, "", ""))
+	assert.Equal("ab", SubInBetween(str, "", "c"))
+	assert.Equal("bc", SubInBetween(str, "a", "d"))
+	assert.Equal("", SubInBetween(str, "a", ""))
+	assert.Equal("", SubInBetween(str, "a", "f"))
+}