feat: add RandFromGivenSlice function (#235)

* feat: add RandFromGivenSlice function

* feat: add RandFromGivenSlice function

random/random.go

@@ -185,6 +185,15 @@ func RandStringSlice(charset string, sliceLen, strLen int) []string {
 	return result
 }
 
+// RandFromGivenSlice generate a random element from given slice.
+func RandFromGivenSlice[T any](slice []T) T {
+	if len(slice) == 0 {
+		var zero T
+		return zero
+	}
+	return slice[rand.Intn(len(slice))]
+}
+
 // RandUpper generate a random upper case string of specified length.
 // Play: https://go.dev/play/p/29QfOh0DVuh
 func RandUpper(length int) string {

random/random_example_test.go

@@ -43,6 +43,24 @@ func ExampleRandString() {
 	// 6
 }
 
+func ExampleRandFromGivenSlice() {
+	goods := []string{"apple", "banana", "cherry", "elderberry", "fig", "grape", "honeydew", "kiwi", "lemon",
+		"mango", "nectarine", "orange"}
+
+	isInGoods := false
+	result := RandFromGivenSlice(goods)
+	for _, good := range goods {
+		if good == result {
+			isInGoods = true
+			break
+		}
+	}
+	fmt.Println(isInGoods)
+
+	// Output:
+	// true
+}
+
 func ExampleRandUpper() {
 	pattern := `^[A-Z]+$`
 	reg := regexp.MustCompile(pattern)

random/random_test.go

@@ -269,6 +269,29 @@ func TestRandStringSlice(t *testing.T) {
 	// })
 }
 
+func TestRandFromGivenSlice(t *testing.T) {
+	t.Parallel()
+	assert := internal.NewAssert(t, "TestRandFromGivenSlice")
+
+	randomSet := []any{"a", 8, "王", true, 1.1}
+	result := RandFromGivenSlice(randomSet)
+	find := false
+	for _, v := range randomSet {
+		if v == result {
+			find = true
+		}
+	}
+	assert.Equal(true, find)
+
+	emptyAnyRandomSet := []any{}
+	emptyAnyResult := RandFromGivenSlice(emptyAnyRandomSet)
+	assert.IsNil(emptyAnyResult)
+
+	emptyIntRandomSet := []int{}
+	emtpyIntResult := RandFromGivenSlice(emptyIntRandomSet)
+	assert.Equal(0, emtpyIntResult)
+}
+
 func TestRandBool(t *testing.T) {
 	t.Parallel()
 	assert := internal.NewAssert(t, "TestRandBool")