feat: add Frequency in slice package

docs/api/packages/slice.md

@@ -105,6 +105,7 @@ import (
 -   [Break](#Break)
 -   [RightPadding](#RightPadding)
 -   [LeftPadding](#LeftPadding)
+-   [Frequency](#Frequency)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -2902,7 +2903,7 @@ func main() {
 }
 ```
 
-<span id="RightPadding">RightPadding</span>
+### <span id="RightPadding">RightPadding</span>
 
 <p>在切片的右部添加元素。</p>
 
@@ -2921,7 +2922,7 @@ import (
 )
 
 func main() {
-      nums := []int{1, 2, 3, 4, 5}
+    nums := []int{1, 2, 3, 4, 5}
     padded := slice.RightPadding(nums, 0, 3)
     fmt.Println(padded)
     // Output:
@@ -2929,7 +2930,7 @@ func main() {
 }
 ```
 
-<span id="LeftPadding">LeftPadding</span>
+### <span id="LeftPadding">LeftPadding</span>
 
 <p>在切片的左部添加元素。</p>
 
@@ -2948,10 +2949,39 @@ import (
 )
 
 func main() {
-      nums := []int{1, 2, 3, 4, 5}
+    nums := []int{1, 2, 3, 4, 5}
     padded := slice.LeftPadding(nums, 0, 3)
     fmt.Println(padded)
     // Output:
     // [0 0 0 1 2 3 4 5]
 }
+```
+
+### <span id="Frequency">Frequency</span>
+
+<p>计算切片中每个元素出现的频率。</p>
+
+<b>函数签名:</b>
+
+```go
+func Frequency[T comparable](slice []T) map[T]int
+```
+
+<b>示例:<span style="float:right;display:inline-block;">[运行]()</span></b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/slice"
+)
+
+func main() {
+    strs := []string{"a", "b", "b", "c", "c", "c"}
+    result := slice.Frequency(strs)
+
+    fmt.Println(result)
+
+    // Output:
+    // map[a:1 b:2 c:3]
+}
 ```

docs/en/api/packages/slice.md

@@ -105,6 +105,7 @@ import (
 -   [Break](#Break)
 -   [RightPadding](#RightPadding)
 -   [LeftPadding](#LeftPadding)
+-   [Frequency](#Frequency)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -2897,7 +2898,7 @@ func main() {
 }
 ```
 
-<span id="c">RightPadding</span>
+### <span id="RightPadding">RightPadding</span>
 
 <p>RightPadding adds padding to the right end of a slice.</p>
 
@@ -2916,7 +2917,7 @@ import (
 )
 
 func main() {
-      nums := []int{1, 2, 3, 4, 5}
+    nums := []int{1, 2, 3, 4, 5}
     padded := slice.RightPadding(nums, 0, 3)
     fmt.Println(padded)
     // Output:
@@ -2924,7 +2925,7 @@ func main() {
 }
 ```
 
-<span id="LeftPadding">LeftPadding</span>
+### <span id="LeftPadding">LeftPadding</span>
 
 <p>LeftPadding adds padding to the left begin of a slice.</p>
 
@@ -2943,10 +2944,39 @@ import (
 )
 
 func main() {
-      nums := []int{1, 2, 3, 4, 5}
+    nums := []int{1, 2, 3, 4, 5}
     padded := slice.LeftPadding(nums, 0, 3)
     fmt.Println(padded)
     // Output:
     // [0 0 0 1 2 3 4 5]
 }
+```
+
+### <span id="Frequency">Frequency</span>
+
+<p>Counts the frequency of each element in the slice.</p>
+
+<b>Signature:</b>
+
+```go
+func Frequency[T comparable](slice []T) map[T]int
+```
+
+<b>Example:<span style="float:right;display:inline-block;">[Run]()</span></b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/slice"
+)
+
+func main() {
+    strs := []string{"a", "b", "b", "c", "c", "c"}
+    result := slice.Frequency(strs)
+
+    fmt.Println(result)
+
+    // Output:
+    // map[a:1 b:2 c:3]
+}
 ```

slice/slice.go

@@ -1386,3 +1386,15 @@ func LeftPadding[T any](slice []T, paddingValue T, paddingLength int) []T {
 
 	return paddedSlice
 }
+
+// Frequency counts the frequency of each element in the slice.
+// Play: todo
+func Frequency[T comparable](slice []T) map[T]int {
+	result := make(map[T]int)
+
+	for _, v := range slice {
+		result[v]++
+	}
+
+	return result
+}

slice/slice_example_test.go

@@ -1251,3 +1251,13 @@ func ExampleMapConcurrent() {
 	// Output:
 	// [1 4 9 16 25 36]
 }
+
+func ExampleFrequency() {
+	strs := []string{"a", "b", "b", "c", "c", "c"}
+	result := Frequency(strs)
+
+	fmt.Println(result)
+
+	// Output:
+	// map[a:1 b:2 c:3]
+}

slice/slice_test.go

@@ -1764,5 +1764,55 @@ func TestFilterConcurrent(t *testing.T) {
 		actual := FilterConcurrent(nums, func(_, n int) bool { return n > 3 }, 4)
 		assert.Equal(expected, actual)
 	})
-
+}
+
+func TestFrequency(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestFrequency")
+
+	t.Run("empty slice", func(t *testing.T) {
+		result := Frequency([]int{})
+		assert.Equal(map[int]int{}, result)
+	})
+
+	t.Run("int slice", func(t *testing.T) {
+		nums := []int{1, 2, 2, 3, 3, 3}
+		expected := map[int]int{1: 1, 2: 2, 3: 3}
+		result := Frequency(nums)
+
+		assert.Equal(expected, result)
+	})
+
+	t.Run("string slice", func(t *testing.T) {
+		strs := []string{"a", "b", "b", "c", "c", "c"}
+		expected := map[string]int{"a": 1, "b": 2, "c": 3}
+		result := Frequency(strs)
+
+		assert.Equal(expected, result)
+	})
+
+	t.Run("struct slice", func(t *testing.T) {
+		type student struct {
+			Name string
+			Age  int
+		}
+
+		students := []student{
+			{Name: "a", Age: 11},
+			{Name: "b", Age: 12},
+			{Name: "a", Age: 13},
+			{Name: "c", Age: 14},
+		}
+
+		expected := map[student]int{
+			{Name: "a", Age: 11}: 1,
+			{Name: "a", Age: 13}: 1,
+			{Name: "b", Age: 12}: 1,
+			{Name: "c", Age: 14}: 1,
+		}
+		result := Frequency(students)
+
+		assert.Equal(expected, result)
+	})
 }