feat: add ReduceRight

README.md

@@ -711,12 +711,16 @@ import "github.com/duke-git/lancet/v2/mathutil"
     [[play](https://go.dev/play/p/akLWz0EqOSM)]
 -   **<big>AngleToRadian</big>** : converts angle value to radian value.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/mathutil.md#AngleToRadian)]
+    [[play](https://go.dev/play/p/CIvlICqrHql)]
 -   **<big>RadianToAngle</big>** : converts radian value to angle value.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/mathutil.md#RadianToAngle)]
+    [[play](https://go.dev/play/p/dQtmOTUOMgi)]
 -   **<big>PointDistance</big>** : get two points distance.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/mathutil.md#PointDistance)]
+    [[play](https://go.dev/play/p/RrG4JIaziM8)]
 -   **<big>IsPrime</big>** : checks if number is prime number.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/mathutil.md#IsPrime)]
+    [[play](https://go.dev/play/p/Rdd8UTHZJ7u)]
 
 ### 13. Netutil package contains functions to get net information and send http request.
 
@@ -1150,6 +1154,8 @@ import "github.com/duke-git/lancet/v2/strutil"
     [[play](https://go.dev/play/p/bj7_odx3vRf)]
 -   **<big>RemoveNonPrintable</big>** : remove non-printable characters from a string.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/strutil.md#RemoveNonPrintable)]
+    [[play](https://go.dev/play/p/og47F5x_jTZ)]
+
 
 ### 19. System package contain some functions about os, runtime, shell command.
 
@@ -1281,8 +1287,10 @@ import "github.com/duke-git/lancet/v2/validator"
     [[play](https://go.dev/play/p/E2nt3unlmzP)]
 -   **<big>IsASCII</big>** : checks if string is all ASCII char.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/validator.md#IsASCII)]
+    [[play](https://go.dev/play/p/hfQNPLX0jNa)]
 -   **<big>IsPrintable</big>** : checks if string is all printable chars.
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/validator.md#IsPrintable)]
+    [[play](https://go.dev/play/p/Pe1FE2gdtTP)]
 
 ### 21. xerror package implements helpers for errors.
 

README_zh-CN.md

@@ -710,12 +710,16 @@ import "github.com/duke-git/lancet/v2/mathutil"
     [[play](https://go.dev/play/p/akLWz0EqOSM)]
 -   **<big>AngleToRadian</big>** : 将角度值转为弧度值。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/mathutil_zh-CN.md#AngleToRadian)]
+    [[play](https://go.dev/play/p/CIvlICqrHql)]
 -   **<big>RadianToAngle</big>** : 将弧度值转为角度值。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/mathutil_zh-CN.md#RadianToAngle)]
+    [[play](https://go.dev/play/p/dQtmOTUOMgi)]
 -   **<big>PointDistance</big>** : 计算两个坐标点的距离。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/mathutil_zh-CN.md#PointDistance)]
+    [[play](https://go.dev/play/p/RrG4JIaziM8)]
 -   **<big>IsPrime</big>** : 判断质数。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/mathutil_zh-CN.md#IsPrime)]
+    [[play](https://go.dev/play/p/Rdd8UTHZJ7u)]
 
 ### 13. netutil 网络包支持获取 ip 地址，发送 http 请求。
 
@@ -1152,6 +1156,7 @@ import "github.com/duke-git/lancet/v2/strutil"
     [[play](https://go.dev/play/p/bj7_odx3vRf)]
 -   **<big>RemoveNonPrintable</big>** : 删除字符串中不可打印的字符。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/strutil_zh-CN.md#RemoveNonPrintable)]
+    [[play](https://go.dev/play/p/og47F5x_jTZ)]
 
 ### 19. system 包含 os, runtime, shell command 的相关函数。
 
@@ -1283,8 +1288,10 @@ import "github.com/duke-git/lancet/v2/validator"
     [[play](https://go.dev/play/p/E2nt3unlmzP)]
 -   **<big>IsASCII</big>** : 验证字符串全部为 ASCII 字符。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/validator_zh-CN.md#IsASCII)]
+    [[play](https://go.dev/play/p/hfQNPLX0jNa)]
 -   **<big>IsPrintable</big>** : 检查字符串是否全部为可打印字符。
     [[doc](https://github.com/duke-git/lancet/blob/main/docs/validator_zh-CN.md#IsPrintable)]
+    [[play](https://go.dev/play/p/Pe1FE2gdtTP)]
 
 ### 21. xerror 包实现一些错误处理函数
 

docs/slice.md

@@ -63,6 +63,8 @@ import (
 -   [Merge](#Merge)
 -   [Reverse](#Reverse)
 -   [Reduce](#Reduce)
+-   [ReduceBy](#ReduceBy)
+-   [ReduceRight](#ReduceRight)
 -   [Replace](#Replace)
 -   [ReplaceAll](#ReplaceAll)
 -   [Repeat](#Repeat)
@@ -1504,6 +1506,72 @@ func main() {
 }
 ```
 
+### <span id="ReduceBy">ReduceBy</span>
+
+<p>Produces a value from slice by accumulating the result of each element as passed through the reducer function.</p>
+
+<b>Signature:</b>
+
+```go
+func ReduceBy[T any, U any](slice []T, initial U, reducer func(index int, item T, agg U) U) U
+```
+
+<b>Example:</b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/slice"
+)
+
+func main() {
+    result1 := slice.ReduceBy([]int{1, 2, 3, 4}, 0, func(_ int, item int, agg int) int {
+        return agg + item
+    })
+
+    result2 := slice.ReduceBy([]int{1, 2, 3, 4}, "", func(_ int, item int, agg string) string {
+        return agg + fmt.Sprintf("%v", item)
+    })
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+
+    // Output:
+    // 10
+    // 1234
+}
+```
+
+### <span id="ReduceRight">ReduceRight</span>
+
+<p>ReduceRight is like ReduceBy, but it iterates over elements of slice from right to left.</p>
+
+<b>Signature:</b>
+
+```go
+func ReduceRight[T any, U any](slice []T, initial U, reducer func(index int, item T, agg U) U) U
+```
+
+<b>Example:</b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/slice"
+)
+
+func main() {
+    result := slice.ReduceRight([]int{1, 2, 3, 4}, "", func(_ int, item int, agg string) string {
+        return agg + fmt.Sprintf("%v", item)
+    })
+
+    fmt.Println(result)
+
+    // Output:
+    // 4321
+}
+```
+
 ### <span id="Replace">Replace</span>
 
 <p>Returns a copy of the slice with the first n non-overlapping instances of old replaced by new.</p>

docs/slice_zh-CN.md

@@ -63,6 +63,8 @@ import (
 -   [Merge](#Merge)
 -   [Reverse](#Reverse)
 -   [Reduce](#Reduce)
+-   [ReduceBy](#ReduceBy)
+-   [ReduceRight](#ReduceRight)
 -   [Replace](#Replace)
 -   [ReplaceAll](#ReplaceAll)
 -   [Repeat](#Repeat)
@@ -1505,6 +1507,72 @@ func main() {
 }
 ```
 
+### <span id="ReduceBy">ReduceBy</span>
+
+<p>对切片中执行reduce操作。</p>
+
+<b>函数签名:</b>
+
+```go
+func ReduceBy[T any, U any](slice []T, initial U, reducer func(index int, item T, agg U) U) U
+```
+
+<b>示例:</b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/slice"
+)
+
+func main() {
+    result1 := slice.ReduceBy([]int{1, 2, 3, 4}, 0, func(_ int, item int, agg int) int {
+        return agg + item
+    })
+
+    result2 := slice.ReduceBy([]int{1, 2, 3, 4}, "", func(_ int, item int, agg string) string {
+        return agg + fmt.Sprintf("%v", item)
+    })
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+
+    // Output:
+    // 10
+    // 1234
+}
+```
+
+### <span id="ReduceRight">ReduceRight</span>
+
+<p>类似ReduceBy操作，迭代切片元素顺序从右至左。</p>
+
+<b>函数签名:</b>
+
+```go
+func ReduceRight[T any, U any](slice []T, initial U, reducer func(index int, item T, agg U) U) U
+```
+
+<b>示例:</b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/slice"
+)
+
+func main() {
+    result := slice.ReduceRight([]int{1, 2, 3, 4}, "", func(_ int, item int, agg string) string {
+        return agg + fmt.Sprintf("%v", item)
+    })
+
+    fmt.Println(result)
+
+    // Output:
+    // 4321
+}
+```
+
 ### <span id="Replace">Replace</span>
 
 <p>返回切片的副本，其中前n个不重叠的old替换为new</p>

mathutil/mathutil.go

@@ -218,21 +218,21 @@ func RangeWithStep[T constraints.Integer | constraints.Float](start, end, step T
 }
 
 // AngleToRadian converts angle value to radian value.
-// Play: todo
+// Play: https://go.dev/play/p/CIvlICqrHql
 func AngleToRadian(angle float64) float64 {
 	radian := angle * (math.Pi / 180)
 	return radian
 }
 
 // RadianToAngle converts radian value to angle value.
-// Play: todo
+// Play: https://go.dev/play/p/dQtmOTUOMgi
 func RadianToAngle(radian float64) float64 {
 	angle := radian * (180 / math.Pi)
 	return angle
 }
 
 // PointDistance get two points distance.
-// Play: todo
+// Play: https://go.dev/play/p/RrG4JIaziM8
 func PointDistance(x1, y1, x2, y2 float64) float64 {
 	a := x1 - x2
 	b := y1 - y2
@@ -242,7 +242,7 @@ func PointDistance(x1, y1, x2, y2 float64) float64 {
 }
 
 // IsPrimes checks if number is prime number.
-// Play: todo
+// Play: https://go.dev/play/p/Rdd8UTHZJ7u
 func IsPrime(n int) bool {
 	if n < 2 {
 		return false

slice/slice.go

@@ -492,6 +492,30 @@ func Reduce[T any](slice []T, iteratee func(index int, item1, item2 T) T, initia
 	return result
 }
 
+// ReduceBy produces a value from slice by accumulating the result of each element as passed through the reducer function.
+// Play: todo
+func ReduceBy[T any, U any](slice []T, initial U, reducer func(index int, item T, agg U) U) U {
+	accumulator := initial
+
+	for i, v := range slice {
+		accumulator = reducer(i, v, accumulator)
+	}
+
+	return accumulator
+}
+
+// ReduceRight is like ReduceBy, but it iterates over elements of slice from right to left.
+// Play: todo
+func ReduceRight[T any, U any](slice []T, initial U, reducer func(index int, item T, agg U) U) U {
+	accumulator := initial
+
+	for i := len(slice) - 1; i >= 0; i-- {
+		accumulator = reducer(i, slice[i], accumulator)
+	}
+
+	return accumulator
+}
+
 // Replace returns a copy of the slice with the first n non-overlapping instances of old replaced by new.
 // Play: https://go.dev/play/p/P5mZp7IhOFo
 func Replace[T comparable](slice []T, old T, new T, n int) []T {

slice/slice_example_test.go

@@ -460,6 +460,34 @@ func ExampleReduce() {
 	// 6
 }
 
+func ExampleReduceBy() {
+	result1 := ReduceBy([]int{1, 2, 3, 4}, 0, func(_ int, item int, agg int) int {
+		return agg + item
+	})
+
+	result2 := ReduceBy([]int{1, 2, 3, 4}, "", func(_ int, item int, agg string) string {
+		return agg + fmt.Sprintf("%v", item)
+	})
+
+	fmt.Println(result1)
+	fmt.Println(result2)
+
+	// Output:
+	// 10
+	// 1234
+}
+
+func ExampleReduceRight() {
+	result := ReduceRight([]int{1, 2, 3, 4}, "", func(_ int, item int, agg string) string {
+		return agg + fmt.Sprintf("%v", item)
+	})
+
+	fmt.Println(result)
+
+	// Output:
+	// 4321
+}
+
 func ExampleReplace() {
 	strs := []string{"a", "b", "c", "a"}
 

slice/slice_test.go

@@ -405,6 +405,32 @@ func TestReduce(t *testing.T) {
 	}
 }
 
+func TestReduceBy(t *testing.T) {
+	assert := internal.NewAssert(t, "TestReduceBy")
+
+	result1 := ReduceBy([]int{1, 2, 3, 4}, 0, func(_ int, item int, agg int) int {
+		return agg + item
+	})
+
+	result2 := ReduceBy([]int{1, 2, 3, 4}, "", func(_ int, item int, agg string) string {
+		return agg + fmt.Sprintf("%v", item)
+	})
+
+	assert.Equal(10, result1)
+	assert.Equal("1234", result2)
+
+}
+
+func TestReduceRight(t *testing.T) {
+	assert := internal.NewAssert(t, "ReduceRight")
+
+	result := ReduceRight([]int{1, 2, 3, 4}, "", func(_ int, item int, agg string) string {
+		return agg + fmt.Sprintf("%v", item)
+	})
+
+	assert.Equal("4321", result)
+}
+
 func TestIntSlice(t *testing.T) {
 	var nums []any
 	nums = append(nums, 1, 2, 3)

strutil/string.go

@@ -362,7 +362,7 @@ func WordCount(s string) int {
 }
 
 // RemoveNonPrintable remove non-printable characters from a string.
-// Play: todo
+// Play: https://go.dev/play/p/og47F5x_jTZ
 func RemoveNonPrintable(str string) string {
 	result := strings.Map(func(r rune) rune {
 		if unicode.IsPrint(r) {

validator/validator.go

@@ -59,7 +59,7 @@ func IsAllLower(str string) bool {
 }
 
 // IsASCII checks if string is all ASCII char.
-// Play: todo
+// Play: https://go.dev/play/p/hfQNPLX0jNa
 func IsASCII(str string) bool {
 	for i := 0; i < len(str); i++ {
 		if str[i] > unicode.MaxASCII {
@@ -70,7 +70,7 @@ func IsASCII(str string) bool {
 }
 
 // IsPrintable checks if string is all printable chars.
-// Play: todo
+// Play: https://go.dev/play/p/Pe1FE2gdtTP
 func IsPrintable(str string) bool {
 	for _, r := range str {
 		if !unicode.IsPrint(r) {