Feature/cut (#102)

anyx/ternary_example_test.go

@@ -4,10 +4,16 @@ import "fmt"
 
 func ExampleTernary() {
 	age := 15
-	res := Ternary(age < 18, "未成年", "成年")
+	res1 := Ternary(age < 18, "未成年", "成年")
+	res2 := Ternary(true, "Yes", "No")
+	res3 := Ternary(false, "Yes", "No")
 
-	fmt.Println(res)
+	fmt.Println(res1)
+	fmt.Println(res2)
+	fmt.Println(res3)
 
 	// Output:
 	// 未成年
+	// Yes
+	// No
 }

strx/cut.go

@@ -0,0 +1,21 @@
+package strx
+
+import "strings"
+
+// Cut 删除 s 中出现的 sub 字符串
+// 第三个参数 n 可选：
+//   - 省略    → 删除所有匹配（等价 strings.ReplaceAll）
+//   - n == 1  → 只删除第一次出现
+//   - n > 1   → 删除前 n 次出现
+func Cut(s, sub string, n ...int) string {
+	if len(sub) == 0 || len(s) == 0 {
+		return s // nothing to do
+	}
+
+	// 默认: 删除所有
+	count := -1
+	if len(n) > 0 {
+		count = n[0]
+	}
+	return strings.Replace(s, sub, "", count)
+}

strx/cut_example_test.go

@@ -0,0 +1,14 @@
+package strx
+
+import (
+	"fmt"
+)
+
+func ExampleCut() {
+	fmt.Println(Cut("this is-AAA", "A"))
+	fmt.Println(Cut("this is-AAA", "A", 1))
+
+	// Output:
+	// this is-
+	// this is-AA
+}

strx/cut_test.go

@@ -0,0 +1,37 @@
+package strx
+
+import (
+	"testing"
+)
+
+func TestCut(t *testing.T) {
+	tests := []struct {
+		name     string
+		s        string
+		sub      string
+		n        int
+		expected string
+	}{
+		{"Remove all", "hello world world", "world", 0, "hello  "},
+		{"Remove once", "hello world world", "world", 1, "hello  world"},
+		{"No sub", "hello world", "", 0, "hello world"},
+		{"No match", "hello world", "abc", 0, "hello world"},
+		{"Empty string", "", "world", 0, ""},
+		{"Remove twice max", "go go go", "go", 2, "  go"},
+		{"Remove all with zero count", "go go go", "go", 0, "  "},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var result string
+			if tt.n > 0 {
+				result = Cut(tt.s, tt.sub, tt.n)
+			} else {
+				result = Cut(tt.s, tt.sub)
+			}
+			if result != tt.expected {
+				t.Errorf("Cut(%q, %q, %v) = %q; want %q", tt.s, tt.sub, tt.n, result, tt.expected)
+			}
+		})
+	}
+}