doc: format code in doc file

docs/convertor.md

@@ -652,45 +652,45 @@ import (
 
 func main() {
     type Struct struct {
-		Str        string
-		Int        int
-		Float      float64
-		Bool       bool
-		Nil        interface{}
-		unexported string
-	}
+        Str        string
+        Int        int
+        Float      float64
+        Bool       bool
+        Nil        interface{}
+        unexported string
+    }
 
-	cases := []interface{}{
-		true,
-		1,
-		0.1,
-		map[string]int{
-			"a": 1,
-			"b": 2,
-		},
-		&Struct{
-			Str:   "test",
-			Int:   1,
-			Float: 0.1,
-			Bool:  true,
-			Nil:   nil,
-			// unexported: "can't be cloned",
-		},
-	}
+    cases := []interface{}{
+        true,
+        1,
+        0.1,
+        map[string]int{
+            "a": 1,
+            "b": 2,
+        },
+        &Struct{
+            Str:   "test",
+            Int:   1,
+            Float: 0.1,
+            Bool:  true,
+            Nil:   nil,
+            // unexported: "can't be cloned",
+        },
+    }
 
-	for _, item := range cases {
-		cloned := convertor.DeepClone(item)
+    for _, item := range cases {
+        cloned := convertor.DeepClone(item)
 
-		isPointerEqual := &cloned == &item
-		fmt.Println(cloned, isPointerEqual)
-	}
+        isPointerEqual := &cloned == &item
+        fmt.Println(cloned, isPointerEqual)
+    }
 
-	// Output:
-	// true false
-	// 1 false
-	// 0.1 false
-	// map[a:1 b:2] false
-	// &{test 1 0.1 true <nil> } false
+    // Output:
+    // true false
+    // 1 false
+    // 0.1 false
+    // map[a:1 b:2] false
+    // &{test 1 0.1 true <nil> } false
 }
 ```
 
@@ -717,43 +717,43 @@ import (
 
 func main() {
     type Address struct {
-		Country string
-		ZipCode string
-	}
+        Country string
+        ZipCode string
+    }
 
-	type User struct {
-		Name   string
-		Age    int
-		Role   string
-		Addr   Address
-		Hobbys []string
-		salary int
-	}
+    type User struct {
+        Name   string
+        Age    int
+        Role   string
+        Addr   Address
+        Hobbys []string
+        salary int
+    }
 
-	type Employee struct {
-		Name   string
-		Age    int
-		Role   string
-		Addr   Address
-		Hobbys []string
-		salary int
-	}
+    type Employee struct {
+        Name   string
+        Age    int
+        Role   string
+        Addr   Address
+        Hobbys []string
+        salary int
+    }
 
-	user := User{Name: "user001", Age: 10, Role: "Admin", Addr: Address{Country: "CN", ZipCode: "001"}, Hobbys: []string{"a", "b"}, salary: 1000}
+    user := User{Name: "user001", Age: 10, Role: "Admin", Addr: Address{Country: "CN", ZipCode: "001"}, Hobbys: []string{"a", "b"}, salary: 1000}
 
-	employee1 := Employee{}
-	CopyProperties(&employee1, &user)
+    employee1 := Employee{}
+    CopyProperties(&employee1, &user)
 
-	employee2 := Employee{Name: "employee001", Age: 20, Role: "User",
-		Addr: Address{Country: "UK", ZipCode: "002"}, salary: 500}
+    employee2 := Employee{Name: "employee001", Age: 20, Role: "User",
+        Addr: Address{Country: "UK", ZipCode: "002"}, salary: 500}
 
-	CopyProperties(&employee2, &user)
+    CopyProperties(&employee2, &user)
 
-	fmt.Println(employee1)
-	fmt.Println(employee2)
+    fmt.Println(employee1)
+    fmt.Println(employee2)
 
-	// Output:
-	// {user001 10 Admin {CN 001} [a b] 0}
-	// {user001 10 Admin {CN 001} [a b] 500}
+    // Output:
+    // {user001 10 Admin {CN 001} [a b] 0}
+    // {user001 10 Admin {CN 001} [a b] 500}
 }
 ```

docs/convertor_zh-CN.md

@@ -652,45 +652,45 @@ import (
 
 func main() {
     type Struct struct {
-		Str        string
-		Int        int
-		Float      float64
-		Bool       bool
-		Nil        interface{}
-		unexported string
-	}
+        Str        string
+        Int        int
+        Float      float64
+        Bool       bool
+        Nil        interface{}
+        unexported string
+    }
 
-	cases := []interface{}{
-		true,
-		1,
-		0.1,
-		map[string]int{
-			"a": 1,
-			"b": 2,
-		},
-		&Struct{
-			Str:   "test",
-			Int:   1,
-			Float: 0.1,
-			Bool:  true,
-			Nil:   nil,
-			// unexported: "can't be cloned",
-		},
-	}
+    cases := []interface{}{
+        true,
+        1,
+        0.1,
+        map[string]int{
+            "a": 1,
+            "b": 2,
+        },
+        &Struct{
+            Str:   "test",
+            Int:   1,
+            Float: 0.1,
+            Bool:  true,
+            Nil:   nil,
+            // unexported: "can't be cloned",
+        },
+    }
 
-	for _, item := range cases {
-		cloned := convertor.DeepClone(item)
+    for _, item := range cases {
+        cloned := convertor.DeepClone(item)
 
-		isPointerEqual := &cloned == &item
-		fmt.Println(cloned, isPointerEqual)
-	}
+        isPointerEqual := &cloned == &item
+        fmt.Println(cloned, isPointerEqual)
+    }
 
-	// Output:
-	// true false
-	// 1 false
-	// 0.1 false
-	// map[a:1 b:2] false
-	// &{test 1 0.1 true <nil> } false
+    // Output:
+    // true false
+    // 1 false
+    // 0.1 false
+    // map[a:1 b:2] false
+    // &{test 1 0.1 true <nil> } false
 }
 ```
 
@@ -716,43 +716,43 @@ import (
 
 func main() {
     type Address struct {
-		Country string
-		ZipCode string
-	}
+        Country string
+        ZipCode string
+    }
 
-	type User struct {
-		Name   string
-		Age    int
-		Role   string
-		Addr   Address
-		Hobbys []string
-		salary int
-	}
+    type User struct {
+        Name   string
+        Age    int
+        Role   string
+        Addr   Address
+        Hobbys []string
+        salary int
+    }
 
-	type Employee struct {
-		Name   string
-		Age    int
-		Role   string
-		Addr   Address
-		Hobbys []string
-		salary int
-	}
+    type Employee struct {
+        Name   string
+        Age    int
+        Role   string
+        Addr   Address
+        Hobbys []string
+        salary int
+    }
 
-	user := User{Name: "user001", Age: 10, Role: "Admin", Addr: Address{Country: "CN", ZipCode: "001"}, Hobbys: []string{"a", "b"}, salary: 1000}
+    user := User{Name: "user001", Age: 10, Role: "Admin", Addr: Address{Country: "CN", ZipCode: "001"}, Hobbys: []string{"a", "b"}, salary: 1000}
 
-	employee1 := Employee{}
-	CopyProperties(&employee1, &user)
+    employee1 := Employee{}
+    CopyProperties(&employee1, &user)
 
-	employee2 := Employee{Name: "employee001", Age: 20, Role: "User",
-		Addr: Address{Country: "UK", ZipCode: "002"}, salary: 500}
+    employee2 := Employee{Name: "employee001", Age: 20, Role: "User",
+        Addr: Address{Country: "UK", ZipCode: "002"}, salary: 500}
 
-	CopyProperties(&employee2, &user)
+    CopyProperties(&employee2, &user)
 
-	fmt.Println(employee1)
-	fmt.Println(employee2)
+    fmt.Println(employee1)
+    fmt.Println(employee2)
 
-	// Output:
-	// {user001 10 Admin {CN 001} [a b] 0}
-	// {user001 10 Admin {CN 001} [a b] 500}
+    // Output:
+    // {user001 10 Admin {CN 001} [a b] 0}
+    // {user001 10 Admin {CN 001} [a b] 500}
 }
 ```

docs/maputil.md

@@ -24,11 +24,23 @@ import (
 
 -   [ForEach](#ForEach)
 -   [Filter](#Filter)
+-   [FilterByKeys](#FilterByKeys)
+-   [FilterByValues](#FilterByValues)
+-   [OmitBy](#OmitBy)
+-   [OmitByKeys](#OmitByKeys)
+-   [OmitByValues](#OmitByValues)
 -   [Intersect](#Intersect)
 -   [Keys](#Keys)
+-   [Values](#Values)
+-   [KeysBy](#KeysBy)
+-   [ValuesBy](#ValuesBy)
+-   [MapKeys](#MapKeys)
+-   [MapValues](#MapValues)
+-   [Entries](#Entries)
+-   [FromEntries](#FromEntries)
+-   [Transform](#Transform)
 -   [Merge](#Merge)
 -   [Minus](#Minus)
--   [Values](#Values)
 -   [IsDisjoint](#IsDisjoint)
 
 <div STYLE="page-break-after: always;"></div>
@@ -121,6 +133,205 @@ func main() {
 }
 ```
 
+
+### <span id="FilterByKeys">FilterByKeys</span>
+
+<p>Iterates over map, return a new map whose keys are all given keys.</p>
+
+<b>Signature:</b>
+
+```go
+func FilterByKeys[K comparable, V any](m map[K]V, keys []K) map[K]V
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+        "d": 4,
+        "e": 5,
+    }
+
+    result := maputil.FilterByKeys(m, []string{"a", "b"})
+
+    fmt.Println(result)
+
+    // Output:
+    // map[a:1 b:2]
+}
+```
+
+
+### <span id="FilterByValues">FilterByValues</span>
+
+<p>Iterates over map, return a new map whose values are all given values.</p>
+
+<b>Signature:</b>
+
+```go
+func FilterByValues[K comparable, V comparable](m map[K]V, values []V) map[K]V
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+        "d": 4,
+        "e": 5,
+    }
+
+    result := maputil.FilterByValues(m, []int{3, 4})
+
+    fmt.Println(result)
+
+    // Output:
+    // map[c:3 d:4]
+}
+```
+
+
+### <span id="OmitBy">OmitBy</span>
+
+<p>OmitBy is the opposite of Filter, removes all the map elements for which the predicate function returns true.</p>
+
+<b>Signature:</b>
+
+```go
+func OmitBy[K comparable, V any](m map[K]V, predicate func(key K, value V) bool) map[K]V
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+        "d": 4,
+        "e": 5,
+    }
+    isEven := func(_ string, value int) bool {
+        return value%2 == 0
+    }
+
+    result := maputil.OmitBy(m, isEven)
+
+    fmt.Println(result)
+
+    // Output:
+    // map[a:1 c:3 e:5]
+}
+```
+
+
+### <span id="OmitByKeys">OmitByKeys</span>
+
+<p>The opposite of FilterByKeys, extracts all the map elements which keys are not omitted.</p>
+
+<b>Signature:</b>
+
+```go
+func OmitByKeys[K comparable, V any](m map[K]V, keys []K) map[K]V
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+        "d": 4,
+        "e": 5,
+    }
+
+    result := maputil.OmitByKeys(m, []string{"a", "b"})
+
+    fmt.Println(result)
+
+    // Output:
+    // map[c:3 d:4 e:5]
+}
+```
+
+
+### <span id="OmitByValues">OmitByValues</span>
+
+<p>The opposite of FilterByValues. remov all elements whose value are in the give slice.</p>
+
+<b>Signature:</b>
+
+```go
+func OmitByValues[K comparable, V comparable](m map[K]V, values []V) map[K]V
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+        "d": 4,
+        "e": 5,
+    }
+
+    result := maputil.OmitByValues(m, []int{4, 5})
+
+    fmt.Println(result)
+
+    // Output:
+    // map[a:1 b:2 c:3]
+}
+```
+
+
 ### <span id="Intersect">Intersect</span>
 
 <p>Iterates over maps, return a new map of key and value pairs in all given maps.</p>
@@ -193,6 +404,7 @@ package main
 
 import (
     "fmt"
+    "sort"
     "github.com/duke-git/lancet/v2/maputil"
 )
 
@@ -313,6 +525,7 @@ package main
 
 import (
     "fmt"
+    "sort"
     "github.com/duke-git/lancet/v2/maputil"
 )
 
@@ -335,6 +548,300 @@ func main() {
 }
 ```
 
+### <span id="KeysBy">KeysBy</span>
+
+<p>Creates a slice whose element is the result of function mapper invoked by every map's key.</p>
+
+<b>Signature:</b>
+
+```go
+func KeysBy[K comparable, V any, T any](m map[K]V, mapper func(item K) T) []T
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "sort"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[int]string{
+        1: "a",
+        2: "a",
+        3: "b",
+    }
+
+    keys := maputil.KeysBy(m, func(n int) int {
+        return n + 1
+    })
+
+    sort.Ints(keys)
+
+    fmt.Println(keys)
+
+    // Output:
+    // [2 3 4]
+}
+```
+
+### <span id="ValuesBy">ValuesBy</span>
+
+<p>Creates a slice whose element is the result of function mapper invoked by every map's value.</p>
+
+<b>Signature:</b>
+
+```go
+func ValuesBy[K comparable, V any, T any](m map[K]V, mapper func(item V) T) []T
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "sort"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[int]string{
+        1: "a",
+        2: "b",
+        3: "c",
+    }
+    values := maputil.ValuesBy(m, func(v string) string {
+        switch v {
+        case "a":
+            return "a-1"
+        case "b":
+            return "b-2"
+        case "c":
+            return "c-3"
+        default:
+            return ""
+        }
+    })
+
+    sort.Strings(values)
+
+    fmt.Println(values)
+
+    // Output:
+    // [a-1 b-2 c-3]
+}
+```
+
+
+### <span id="MapKeys">MapKeys</span>
+
+<p>Transforms a map to other type map by manipulating it's keys.</p>
+
+<b>Signature:</b>
+
+```go
+func MapKeys[K comparable, V any, T comparable](m map[K]V, iteratee func(key K, value V) T) map[T]V
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "strconv"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[int]string{
+        1: "a",
+        2: "b",
+        3: "c",
+    }
+
+    result := maputil.MapKeys(m, func(k int, _ string) string {
+        return strconv.Itoa(k)
+    })
+
+    fmt.Println(result)
+
+    // Output:
+    // map[1:a 2:b 3:c]
+}
+```
+
+### <span id="MapValues">MapValues</span>
+
+<p>Transforms a map to other type map by manipulating it's values.</p>
+
+<b>Signature:</b>
+
+```go
+func MapValues[K comparable, V any, T any](m map[K]V, iteratee func(key K, value V) T) map[K]T
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "strconv"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[int]string{
+        1: "a",
+        2: "b",
+        3: "c",
+    }
+
+    result := maputil.MapValues(m, func(k int, v string) string {
+        return v + strconv.Itoa(k)
+    })
+
+    fmt.Println(result)
+
+    // Output:
+    // map[1:a1 2:b2 3:c3]
+}
+```
+
+
+### <span id="Entry">Entry</span>
+
+<p>Transforms a map into array of key/value pairs.</p>
+
+<b>Signature:</b>
+
+```go
+type Entry[K comparable, V any] struct {
+    Key   K
+    Value V
+}
+func Entries[K comparable, V any](m map[K]V) []Entry[K, V]
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "sort"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+    }
+
+    result := maputil.Entries(m)
+
+    sort.Slice(result, func(i, j int) bool {
+        return result[i].Value < result[j].Value
+    })
+
+    fmt.Println(result)
+
+    // Output:
+    // [{a 1} {b 2} {c 3}]
+}
+```
+
+
+### <span id="FromEntries">FromEntries</span>
+
+<p>Creates a map based on a slice of key/value pairs.</p>
+
+<b>Signature:</b>
+
+```go
+type Entry[K comparable, V any] struct {
+    Key   K
+    Value V
+}
+func FromEntries[K comparable, V any](entries []Entry[K, V]) map[K]V
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    result := maputil.FromEntries([]Entry[string, int]{
+        {Key: "a", Value: 1},
+        {Key: "b", Value: 2},
+        {Key: "c", Value: 3},
+    })
+
+    fmt.Println(result)
+
+    // Output:
+    // map[a:1 b:2 c:3]
+}
+```
+
+### <span id="Transform">Transform</span>
+
+<p>Transform a map to another type map.</p>
+
+<b>Signature:</b>
+
+```go
+func Transform[K1 comparable, V1 any, K2 comparable, V2 any](m map[K1]V1, iteratee func(key K1, value V1) (K2, V2)) map[K2]V2
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "strconv"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+    }
+
+    result := Transform(m, func(k string, v int) (string, string) {
+        return k, strconv.Itoa(v)
+    })
+
+    fmt.Println(result)
+
+    // Output:
+    // map[a:1 b:2 c:3]
+}
+```
+
+
 ### <span id="IsDisjoint">IsDisjoint</span>
 
 <p>Checks two maps are disjoint if they have no keys in common</p>

docs/maputil_zh-CN.md

@@ -24,11 +24,23 @@ import (
 
 -   [ForEach](#ForEach)
 -   [Filter](#Filter)
+-   [FilterByKeys](#FilterByKeys)
+-   [FilterByValues](#FilterByValues)
+-   [OmitBy](#OmitBy)
+-   [OmitByKeys](#OmitByKeys)
+-   [OmitByValues](#OmitByValues)
 -   [Intersect](#Intersect)
 -   [Keys](#Keys)
+-   [Values](#Values)
+-   [KeysBy](#KeysBy)
+-   [ValuesBy](#ValuesBy)
+-   [MapKeys](#MapKeys)
+-   [MapValues](#MapValues)
+-   [Entries](#Entries)
+-   [FromEntries](#FromEntries)
+-   [Transform](#Transform)
 -   [Merge](#Merge)
 -   [Minus](#Minus)
--   [Values](#Values)
 -   [IsDisjoint](#IsDisjoint)
 
 <div STYLE="page-break-after: always;"></div>
@@ -121,6 +133,203 @@ func main() {
 }
 ```
 
+### <span id="FilterByKeys">FilterByKeys</span>
+
+<p>迭代map, 返回一个新map，其key都是给定的key值.</p>
+
+<b>函数签名:</b>
+
+```go
+func FilterByKeys[K comparable, V any](m map[K]V, keys []K) map[K]V
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+        "d": 4,
+        "e": 5,
+    }
+
+    result := maputil.FilterByKeys(m, []string{"a", "b"})
+
+    fmt.Println(result)
+
+    // Output:
+    // map[a:1 b:2]
+}
+```
+
+
+### <span id="FilterByValues">FilterByValues</span>
+
+<p>迭代map, 返回一个新map，其value都是给定的value值.</p>
+
+<b>函数签名:</b>
+
+```go
+func FilterByValues[K comparable, V comparable](m map[K]V, values []V) map[K]V
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+        "d": 4,
+        "e": 5,
+    }
+
+    result := maputil.FilterByValues(m, []int{3, 4})
+
+    fmt.Println(result)
+
+    // Output:
+    // map[c:3 d:4]
+}
+```
+
+
+### <span id="OmitBy">OmitBy</span>
+
+<p>Filter的反向操作, 迭代map中的每对key和value, 删除符合predicate函数的key, value, 返回新map</p>
+
+<b>函数签名:</b>
+
+```go
+func OmitBy[K comparable, V any](m map[K]V, predicate func(key K, value V) bool) map[K]V
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+        "d": 4,
+        "e": 5,
+    }
+    isEven := func(_ string, value int) bool {
+        return value%2 == 0
+    }
+
+    result := maputil.OmitBy(m, isEven)
+
+    fmt.Println(result)
+
+    // Output:
+    // map[a:1 c:3 e:5]
+}
+```
+
+
+### <span id="OmitByKeys">OmitByKeys</span>
+
+<p>FilterByKeys的反向操作, 迭代map, 返回一个新map，其key不包括给定的key值.</p>
+
+<b>函数签名:</b>
+
+```go
+func OmitByKeys[K comparable, V any](m map[K]V, keys []K) map[K]V
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+        "d": 4,
+        "e": 5,
+    }
+
+    result := maputil.OmitByKeys(m, []string{"a", "b"})
+
+    fmt.Println(result)
+
+    // Output:
+    // map[c:3 d:4 e:5]
+}
+```
+
+
+### <span id="OmitByValues">OmitByValues</span>
+
+<p>FilterByValues的反向操作, 迭代map, 返回一个新map，其value不包括给定的value值.</p>
+
+<b>函数签名:</b>
+
+```go
+func OmitByValues[K comparable, V comparable](m map[K]V, values []V) map[K]V
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+        "d": 4,
+        "e": 5,
+    }
+
+    result := maputil.OmitByValues(m, []int{4, 5})
+
+    fmt.Println(result)
+
+    // Output:
+    // map[a:1 b:2 c:3]
+}
+```
+
 ### <span id="Intersect">Intersect</span>
 
 <p>多个map的交集操作</p>
@@ -333,6 +542,299 @@ func main() {
 }
 ```
 
+### <span id="KeysBy">KeysBy</span>
+
+<p>创建一个切片，其元素是每个map的key调用mapper函数的结果。</p>
+
+<b>函数签名:</b>
+
+```go
+func KeysBy[K comparable, V any, T any](m map[K]V, mapper func(item K) T) []T
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "sort"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[int]string{
+        1: "a",
+        2: "a",
+        3: "b",
+    }
+
+    keys := maputil.KeysBy(m, func(n int) int {
+        return n + 1
+    })
+
+    sort.Ints(keys)
+
+    fmt.Println(keys)
+
+    // Output:
+    // [2 3 4]
+}
+```
+
+### <span id="ValuesBy">ValuesBy</span>
+
+<p>创建一个切片，其元素是每个map的value调用mapper函数的结果。</p>
+
+<b>函数签名:</b>
+
+```go
+func ValuesBy[K comparable, V any, T any](m map[K]V, mapper func(item V) T) []T
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "sort"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[int]string{
+        1: "a",
+        2: "b",
+        3: "c",
+    }
+    values := maputil.ValuesBy(m, func(v string) string {
+        switch v {
+        case "a":
+            return "a-1"
+        case "b":
+            return "b-2"
+        case "c":
+            return "c-3"
+        default:
+            return ""
+        }
+    })
+
+    sort.Strings(values)
+
+    fmt.Println(values)
+
+    // Output:
+    // [a-1 b-2 c-3]
+}
+```
+
+
+### <span id="MapKeys">MapKeys</span>
+
+<p>操作map的每个key，然后转为新的map。</p>
+
+<b>函数签名:</b>
+
+```go
+func MapKeys[K comparable, V any, T comparable](m map[K]V, iteratee func(key K, value V) T) map[T]V
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "strconv"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[int]string{
+        1: "a",
+        2: "b",
+        3: "c",
+    }
+
+    result := maputil.MapKeys(m, func(k int, _ string) string {
+        return strconv.Itoa(k)
+    })
+
+    fmt.Println(result)
+
+    // Output:
+    // map[1:a 2:b 3:c]
+}
+```
+
+### <span id="MapValues">MapValues</span>
+
+<p>操作map的每个value，然后转为新的map。</p>
+
+<b>函数签名:</b>
+
+```go
+func MapValues[K comparable, V any, T any](m map[K]V, iteratee func(key K, value V) T) map[K]T
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "strconv"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[int]string{
+        1: "a",
+        2: "b",
+        3: "c",
+    }
+
+    result := maputil.MapValues(m, func(k int, v string) string {
+        return v + strconv.Itoa(k)
+    })
+
+    fmt.Println(result)
+
+    // Output:
+    // map[1:a1 2:b2 3:c3]
+}
+```
+
+
+### <span id="Entry">Entry</span>
+
+<p>将map转换为键/值对切片。</p>
+
+<b>函数签名:</b>
+
+```go
+type Entry[K comparable, V any] struct {
+    Key   K
+    Value V
+}
+func Entries[K comparable, V any](m map[K]V) []Entry[K, V]
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "sort"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+    }
+
+    result := maputil.Entries(m)
+
+    sort.Slice(result, func(i, j int) bool {
+        return result[i].Value < result[j].Value
+    })
+
+    fmt.Println(result)
+
+    // Output:
+    // [{a 1} {b 2} {c 3}]
+}
+```
+
+
+### <span id="FromEntries">FromEntries</span>
+
+<p>基于键/值对的切片创建map。</p>
+
+<b>函数签名:</b>
+
+```go
+type Entry[K comparable, V any] struct {
+    Key   K
+    Value V
+}
+func FromEntries[K comparable, V any](entries []Entry[K, V]) map[K]V
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    result := maputil.FromEntries([]Entry[string, int]{
+        {Key: "a", Value: 1},
+        {Key: "b", Value: 2},
+        {Key: "c", Value: 3},
+    })
+
+    fmt.Println(result)
+
+    // Output:
+    // map[a:1 b:2 c:3]
+}
+```
+
+### <span id="Transform">Transform</span>
+
+<p>将map转换为其他类型的map。</p>
+
+<b>函数签名:</b>
+
+```go
+func Transform[K1 comparable, V1 any, K2 comparable, V2 any](m map[K1]V1, iteratee func(key K1, value V1) (K2, V2)) map[K2]V2
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "strconv"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+    m := map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+    }
+
+    result := Transform(m, func(k string, v int) (string, string) {
+        return k, strconv.Itoa(v)
+    })
+
+    fmt.Println(result)
+
+    // Output:
+    // map[a:1 b:2 c:3]
+}
+```
+
 ### <span id="IsDisjoint">IsDisjoint</span>
 
 <p>验证两个map是否具有不同的key</p>

docs/strutil.md

@@ -43,6 +43,8 @@ import (
 -   [Substring](#Substring)
 -   [Wrap](#Wrap)
 -   [Unwrap](#Unwrap)
+-   [SplitWords](#SplitWords)
+-   [WordCount](#WordCount)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -470,28 +472,28 @@ import (
 
 func main() {
     result1 := strutil.Pad("foo", 1, "bar")
-	result2 := strutil.Pad("foo", 2, "bar")
-	result3 := strutil.Pad("foo", 3, "bar")
-	result4 := strutil.Pad("foo", 4, "bar")
-	result5 := strutil.Pad("foo", 5, "bar")
-	result6 := strutil.Pad("foo", 6, "bar")
-	result7 := strutil.Pad("foo", 7, "bar")
+    result2 := strutil.Pad("foo", 2, "bar")
+    result3 := strutil.Pad("foo", 3, "bar")
+    result4 := strutil.Pad("foo", 4, "bar")
+    result5 := strutil.Pad("foo", 5, "bar")
+    result6 := strutil.Pad("foo", 6, "bar")
+    result7 := strutil.Pad("foo", 7, "bar")
 
-	fmt.Println(result1)
-	fmt.Println(result2)
-	fmt.Println(result3)
-	fmt.Println(result4)
-	fmt.Println(result5)
-	fmt.Println(result6)
-	fmt.Println(result7)
-	// Output:
-	// foo
-	// foo
-	// foo
-	// foob
-	// bfoob
-	// bfooba
-	// bafooba
+    fmt.Println(result1)
+    fmt.Println(result2)
+    fmt.Println(result3)
+    fmt.Println(result4)
+    fmt.Println(result5)
+    fmt.Println(result6)
+    fmt.Println(result7)
+    // Output:
+    // foo
+    // foo
+    // foo
+    // foob
+    // bfoob
+    // bfooba
+    // bafooba
 }
 ```
 
@@ -848,3 +850,91 @@ func main() {
     // *foo*
 }
 ```
+
+
+### <span id="SplitWords">SplitWords</span>
+
+<p>Splits a string into words, word only contains alphabetic characters.</p>
+
+<b>Signature:</b>
+
+```go
+func SplitWords(s string) []string
+```
+
+<b>Example:</b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/strutil"
+)
+
+func main() {
+    result1 := strutil.SplitWords("a word")
+    result2 := strutil.SplitWords("I'am a programmer")
+    result3 := strutil.SplitWords("Bonjour, je suis programmeur")
+    result4 := strutil.SplitWords("a -b-c' 'd'e")
+    result5 := strutil.SplitWords("你好，我是一名码农")
+    result6 := strutil.SplitWords("こんにちは，私はプログラマーです")
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+    fmt.Println(result3)
+    fmt.Println(result4)
+    fmt.Println(result5)
+    fmt.Println(result6)
+
+    // Output:
+    // [a word]
+    // [I'am a programmer]
+    // [Bonjour je suis programmeur]
+    // [a b-c' d'e]
+    // []
+    // []
+}
+```
+
+
+### <span id="WordCount">WordCount</span>
+
+<p>Return the number of meaningful word, word only contains alphabetic characters.</p>
+
+<b>Signature:</b>
+
+```go
+func WordCount(s string) int
+```
+
+<b>Example:</b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/strutil"
+)
+
+func main() {
+    result1 := strutil.WordCount("a word")
+    result2 := strutil.WordCount("I'am a programmer")
+    result3 := strutil.WordCount("Bonjour, je suis programmeur")
+    result4 := strutil.WordCount("a -b-c' 'd'e")
+    result5 := strutil.WordCount("你好，我是一名码农")
+    result6 := strutil.WordCount("こんにちは，私はプログラマーです")
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+    fmt.Println(result3)
+    fmt.Println(result4)
+    fmt.Println(result5)
+    fmt.Println(result6)
+
+    // Output:
+    // 2
+    // 3
+    // 4
+    // 3
+    // 0
+    // 0
+}
+```

docs/strutil_zh-CN.md

@@ -42,6 +42,8 @@ import (
 -   [Substring](#Substring)
 -   [Wrap](#Wrap)
 -   [Unwrap](#Unwrap)
+-   [SplitWords](#SplitWords)
+-   [WordCount](#WordCount)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -469,28 +471,28 @@ import (
 
 func main() {
     result1 := strutil.Pad("foo", 1, "bar")
-	result2 := strutil.Pad("foo", 2, "bar")
-	result3 := strutil.Pad("foo", 3, "bar")
-	result4 := strutil.Pad("foo", 4, "bar")
-	result5 := strutil.Pad("foo", 5, "bar")
-	result6 := strutil.Pad("foo", 6, "bar")
-	result7 := strutil.Pad("foo", 7, "bar")
+    result2 := strutil.Pad("foo", 2, "bar")
+    result3 := strutil.Pad("foo", 3, "bar")
+    result4 := strutil.Pad("foo", 4, "bar")
+    result5 := strutil.Pad("foo", 5, "bar")
+    result6 := strutil.Pad("foo", 6, "bar")
+    result7 := strutil.Pad("foo", 7, "bar")
 
-	fmt.Println(result1)
-	fmt.Println(result2)
-	fmt.Println(result3)
-	fmt.Println(result4)
-	fmt.Println(result5)
-	fmt.Println(result6)
-	fmt.Println(result7)
-	// Output:
-	// foo
-	// foo
-	// foo
-	// foob
-	// bfoob
-	// bfooba
-	// bafooba
+    fmt.Println(result1)
+    fmt.Println(result2)
+    fmt.Println(result3)
+    fmt.Println(result4)
+    fmt.Println(result5)
+    fmt.Println(result6)
+    fmt.Println(result7)
+    // Output:
+    // foo
+    // foo
+    // foo
+    // foob
+    // bfoob
+    // bfooba
+    // bafooba
 }
 ```
 
@@ -847,3 +849,90 @@ func main() {
     // *foo*
 }
 ```
+
+### <span id="SplitWords">SplitWords</span>
+
+<p>将字符串拆分为单词，只支持字母字符单词。</p>
+
+<b>函数签名:</b>
+
+```go
+func SplitWords(s string) []string
+```
+
+<b>示例:</b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/strutil"
+)
+
+func main() {
+    result1 := strutil.SplitWords("a word")
+    result2 := strutil.SplitWords("I'am a programmer")
+    result3 := strutil.SplitWords("Bonjour, je suis programmeur")
+    result4 := strutil.SplitWords("a -b-c' 'd'e")
+    result5 := strutil.SplitWords("你好，我是一名码农")
+    result6 := strutil.SplitWords("こんにちは，私はプログラマーです")
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+    fmt.Println(result3)
+    fmt.Println(result4)
+    fmt.Println(result5)
+    fmt.Println(result6)
+
+    // Output:
+    // [a word]
+    // [I'am a programmer]
+    // [Bonjour je suis programmeur]
+    // [a b-c' d'e]
+    // []
+    // []
+}
+```
+
+
+### <span id="WordCount">WordCount</span>
+
+<p>返回有意义单词的数量，只支持字母字符单词。</p>
+
+<b>函数签名:</b>
+
+```go
+func WordCount(s string) int
+```
+
+<b>示例:</b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/strutil"
+)
+
+func main() {
+    result1 := strutil.WordCount("a word")
+    result2 := strutil.WordCount("I'am a programmer")
+    result3 := strutil.WordCount("Bonjour, je suis programmeur")
+    result4 := strutil.WordCount("a -b-c' 'd'e")
+    result5 := strutil.WordCount("你好，我是一名码农")
+    result6 := strutil.WordCount("こんにちは，私はプログラマーです")
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+    fmt.Println(result3)
+    fmt.Println(result4)
+    fmt.Println(result5)
+    fmt.Println(result6)
+
+    // Output:
+    // 2
+    // 3
+    // 4
+    // 3
+    // 0
+    // 0
+}
+```

maputil/map_example_test.go

@@ -343,3 +343,57 @@ func ExampleMapValues() {
 	// Output:
 	// map[1:a1 2:b2 3:c3]
 }
+
+func ExampleOmitBy() {
+	m := map[string]int{
+		"a": 1,
+		"b": 2,
+		"c": 3,
+		"d": 4,
+		"e": 5,
+	}
+	isEven := func(_ string, value int) bool {
+		return value%2 == 0
+	}
+
+	result := OmitBy(m, isEven)
+
+	fmt.Println(result)
+
+	// Output:
+	// map[a:1 c:3 e:5]
+}
+
+func ExampleOmitByKeys() {
+	m := map[string]int{
+		"a": 1,
+		"b": 2,
+		"c": 3,
+		"d": 4,
+		"e": 5,
+	}
+
+	result := OmitByKeys(m, []string{"a", "b"})
+
+	fmt.Println(result)
+
+	// Output:
+	// map[c:3 d:4 e:5]
+}
+
+func ExampleOmitByValues() {
+	m := map[string]int{
+		"a": 1,
+		"b": 2,
+		"c": 3,
+		"d": 4,
+		"e": 5,
+	}
+
+	result := OmitByValues(m, []int{4, 5})
+
+	fmt.Println(result)
+
+	// Output:
+	// map[a:1 b:2 c:3]
+}