fix: fix issue #168

docs/api/packages/strutil.md

@@ -60,6 +60,7 @@ import (
 -   [ContainsAll](#ContainsAll)
 -   [ContainsAny](#ContainsAny)
 -   [RemoveWhiteSpace](#RemoveWhiteSpace)
+-   [SubInBetween](#SubInBetween)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -1096,10 +1097,10 @@ import (
 
 func main() {
     result1 := strutil.IsNotBlank("")
-    result2 := strutil.IsNotBlank("	")
+    result2 := strutil.IsNotBlank("    ")
     result3 := strutil.IsNotBlank("\t\v\f\n")
     result4 := strutil.IsNotBlank(" 中文")
-    result5 := strutil.IsNotBlank(" 	world	")
+    result5 := strutil.IsNotBlank("     world    ")
     
     fmt.Println(result1)
     fmt.Println(result2)
@@ -1462,3 +1463,36 @@ func main() {
     // hello world
 }
 ```
+
+### <span id="SubInBetween">SubInBetween</span>
+
+<p>获取字符串中指定的起始字符串start和终止字符串end直接的子字符串。</p>
+
+<b>函数签名:</b>
+
+```go
+func SubInBetween(str string, start string, end string) string
+```
+
+<b>示例:</b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/strutil"
+)
+
+func main() {
+    str := "abcde"
+
+    result1 := strutil.SubInBetween(str, "", "de")
+    result2 := strutil.SubInBetween(str, "a", "d")
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+
+    // Output:
+    // abc
+    // bc
+}
+```

docs/en/api/packages/strutil.md

@@ -1463,3 +1463,37 @@ func main() {
     // hello world
 }
 ```
+
+
+### <span id="SubInBetween">SubInBetween</span>
+
+<p>Return substring between the start and end position(excluded) of source string.</p>
+
+<b>Signature:</b>
+
+```go
+func SubInBetween(str string, start string, end string) string
+```
+
+<b>Example:</b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/strutil"
+)
+
+func main() {
+    str := "abcde"
+
+    result1 := strutil.SubInBetween(str, "", "de")
+    result2 := strutil.SubInBetween(str, "a", "d")
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+
+    // Output:
+    // abc
+    // bc
+}
+```

strutil/string.go

@@ -121,40 +121,48 @@ func UpperSnakeCase(s string) string {
 // Before returns the substring of the source string up to the first occurrence of the specified string.
 // Play: https://go.dev/play/p/JAWTZDS4F5w
 func Before(s, char string) string {
-	if s == "" || char == "" {
+	i := strings.Index(s, char)
+
+	if s == "" || char == "" || i == -1 {
 		return s
 	}
-	i := strings.Index(s, char)
+
 	return s[0:i]
 }
 
 // BeforeLast returns the substring of the source string up to the last occurrence of the specified string.
 // Play: https://go.dev/play/p/pJfXXAoG_Te
 func BeforeLast(s, char string) string {
-	if s == "" || char == "" {
+	i := strings.LastIndex(s, char)
+
+	if s == "" || char == "" || i == -1 {
 		return s
 	}
-	i := strings.LastIndex(s, char)
+
 	return s[0:i]
 }
 
 // After returns the substring after the first occurrence of a specified string in the source string.
 // Play: https://go.dev/play/p/RbCOQqCDA7m
 func After(s, char string) string {
-	if s == "" || char == "" {
+	i := strings.Index(s, char)
+
+	if s == "" || char == "" || i == -1 {
 		return s
 	}
-	i := strings.Index(s, char)
+
 	return s[i+len(char):]
 }
 
 // AfterLast returns the substring after the last occurrence of a specified string in the source string.
 // Play: https://go.dev/play/p/1TegARrb8Yn
 func AfterLast(s, char string) string {
-	if s == "" || char == "" {
+	i := strings.LastIndex(s, char)
+
+	if s == "" || char == "" || i == -1 {
 		return s
 	}
-	i := strings.LastIndex(s, char)
+
 	return s[i+len(char):]
 }
 
@@ -574,3 +582,15 @@ func RemoveWhiteSpace(str string, repalceAll bool) string {
 
 	return strings.TrimSpace(str)
 }
+
+// SubInBetween return substring between the start and end position(excluded) of source string.
+// Play: todo
+func SubInBetween(str string, start string, end string) string {
+	if _, after, ok := strings.Cut(str, start); ok {
+		if before, _, ok := strings.Cut(after, end); ok {
+			return before
+		}
+	}
+
+	return ""
+}

strutil/string_example_test.go

@@ -653,3 +653,17 @@ func ExampleRemoveWhiteSpace() {
 	// helloworld
 	// hello world
 }
+
+func ExampleSubInBetween() {
+	str := "abcde"
+
+	result1 := SubInBetween(str, "", "de")
+	result2 := SubInBetween(str, "a", "d")
+
+	fmt.Println(result1)
+	fmt.Println(result2)
+
+	// Output:
+	// abc
+	// bc
+}

strutil/string_test.go

@@ -230,6 +230,8 @@ func TestBefore(t *testing.T) {
 
 	assert.Equal("lancet", Before("lancet", ""))
 	assert.Equal("", Before("lancet", "lancet"))
+	assert.Equal("lancet", Before("lancet", "abcdef"))
+
 	assert.Equal("github.com", Before("github.com/test/lancet", "/"))
 	assert.Equal("github.com/", Before("github.com/test/lancet", "test"))
 }
@@ -240,10 +242,10 @@ func TestBeforeLast(t *testing.T) {
 	assert := internal.NewAssert(t, "TestBeforeLast")
 
 	assert.Equal("lancet", BeforeLast("lancet", ""))
+	assert.Equal("lancet", BeforeLast("lancet", "abcdef"))
+
 	assert.Equal("github.com/test", BeforeLast("github.com/test/lancet", "/"))
 	assert.Equal("github.com/test/", BeforeLast("github.com/test/test/lancet", "test"))
-
-	assert.NotEqual("github.com/", BeforeLast("github.com/test/test/lancet", "test"))
 }
 
 func TestAfter(t *testing.T) {
@@ -255,6 +257,8 @@ func TestAfter(t *testing.T) {
 	assert.Equal("", After("lancet", "lancet"))
 	assert.Equal("test/lancet", After("github.com/test/lancet", "/"))
 	assert.Equal("/lancet", After("github.com/test/lancet", "test"))
+
+	assert.Equal("lancet", After("lancet", "abcdef"))
 }
 
 func TestAfterLast(t *testing.T) {
@@ -266,8 +270,7 @@ func TestAfterLast(t *testing.T) {
 	assert.Equal("lancet", AfterLast("github.com/test/lancet", "/"))
 	assert.Equal("/lancet", AfterLast("github.com/test/lancet", "test"))
 	assert.Equal("/lancet", AfterLast("github.com/test/test/lancet", "test"))
-
-	assert.NotEqual("/test/lancet", AfterLast("github.com/test/test/lancet", "test"))
+	assert.Equal("lancet", AfterLast("lancet", "abcdef"))
 }
 
 func TestIsString(t *testing.T) {
@@ -566,3 +569,15 @@ func TestRemoveWhiteSpace(t *testing.T) {
 	assert.Equal("helloworld", RemoveWhiteSpace(str, true))
 	assert.Equal("hello world", RemoveWhiteSpace(str, false))
 }
+
+func TestSubInBetween(t *testing.T) {
+	assert := internal.NewAssert(t, "TestSubInBetween")
+
+	str := "abcde"
+
+	assert.Equal("", SubInBetween(str, "", ""))
+	assert.Equal("ab", SubInBetween(str, "", "c"))
+	assert.Equal("bc", SubInBetween(str, "a", "d"))
+	assert.Equal("", SubInBetween(str, "a", ""))
+	assert.Equal("", SubInBetween(str, "a", "f"))
+}