feat: add Rotate for string

strutil/string.go

@@ -676,3 +676,31 @@ func Shuffle(str string) string {
 
 	return string(runes)
 }
+
+// Rotate rotates the string by the specified number of characters.
+// Play: todo
+func Rotate(str string, shift int) string {
+	if shift == 0 {
+		return str
+	}
+
+	runes := []rune(str)
+	length := len(runes)
+	if length == 0 {
+		return str
+	}
+
+	shift = shift % length
+
+	if shift < 0 {
+		shift = length + shift
+	}
+
+	var sb strings.Builder
+	sb.Grow(length)
+
+	sb.WriteString(string(runes[length-shift:]))
+	sb.WriteString(string(runes[:length-shift]))
+
+	return sb.String()
+}

strutil/string_example_test.go

@@ -709,3 +709,18 @@ func ExampleEllipsis() {
 	// 你好...
 	// 😀😃😄...
 }
+
+func ExampleRotate() {
+	result1 := Rotate("Hello", 0)
+	result2 := Rotate("Hello", 1)
+	result3 := Rotate("Hello", 2)
+
+	fmt.Println(result1)
+	fmt.Println(result2)
+	fmt.Println(result3)
+
+	// Output:
+	// Hello
+	// oHell
+	// loHel
+}

strutil/string_test.go

@@ -710,9 +710,9 @@ func TestEllipsis(t *testing.T) {
 	assert := internal.NewAssert(t, "TestEllipsis")
 
 	tests := []struct {
-		input  string
-		length int
-		want   string
+		input    string
+		length   int
+		expected string
 	}{
 		{"", 0, ""},
 		{"hello world", 0, ""},
@@ -725,7 +725,7 @@ func TestEllipsis(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		assert.Equal(tt.want, Ellipsis(tt.input, tt.length))
+		assert.Equal(tt.expected, Ellipsis(tt.input, tt.length))
 	}
 }
 
@@ -741,3 +741,28 @@ func TestShuffle(t *testing.T) {
 	shuffledStr := Shuffle(str)
 	assert.Equal(5, len(shuffledStr))
 }
+
+func TestRotate(t *testing.T) {
+	t.Parallel()
+
+	assert := internal.NewAssert(t, "TestRotate")
+
+	tests := []struct {
+		input    string
+		shift    int
+		expected string
+	}{
+		{"", 1, ""},
+		{"a", 0, "a"},
+		{"a", 1, "a"},
+		{"a", -1, "a"},
+
+		{"Hello", -2, "lloHe"},
+		{"Hello", 1, "oHell"},
+		{"Hello, world!", 3, "ld!Hello, wor"},
+	}
+
+	for _, tt := range tests {
+		assert.Equal(tt.expected, Rotate(tt.input, tt.shift))
+	}
+}