feat: add stringx to lang pkg

.gitignore

@@ -13,3 +13,7 @@
 
 # Dependency directories (remove the comment below to include it)
 # vendor/
+
+# IDE or Editor's config
+.idea/
+

lang/stringx/README.md

@@ -0,0 +1,9 @@
+# stringx 
+
+## Introduction
+Extension/Helper of String Operation.
+
+## Features
+- Transform(Reverse, Rotate, Shuffle ...)
+- Construction(Pad, Repeat...)
+- Matching(IsAlpha, IsAlphanumeric, IsNumeric ...)

lang/stringx/doc.go

@@ -0,0 +1,16 @@
+// Copyright 2021 ByteDance Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package stringx provides extensions of string Operation.
+package stringx

lang/stringx/exmaple_test.go

@@ -0,0 +1,76 @@
+// Copyright 2021 ByteDance Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package stringx
+
+import (
+	"fmt"
+	"unicode/utf8"
+)
+
+func Example_sub() {
+	fmt.Printf("Sub-[0:100]=%s\n", Sub("", 0, 100))
+	fmt.Printf("Sub-facgbheidjk[3:9]=%s\n", Sub("facgbheidjk", 3, 9))
+	fmt.Printf("Sub-facgbheidjk[-50:100]=%s\n", Sub("facgbheidjk", -50, 100))
+	fmt.Printf("Sub-facgbheidjk[-3:length]=%s\n", Sub("facgbheidjk", -3, utf8.RuneCountInString("facgbheidjk")))
+	fmt.Printf("Sub-facgbheidjk[-3:-1]=%s\n", Sub("facgbheidjk", -3, -1))
+	fmt.Printf("Sub-zh英文hun排[2:5]=%s\n", Sub("zh英文hun排", 2, 5))
+	fmt.Printf("Sub-zh英文hun排[2:-1]=%s\n", Sub("zh英文hun排", 2, -1))
+	fmt.Printf("Sub-zh英文hun排[-100:-1]=%s\n", Sub("zh英文hun排", -100, -1))
+	fmt.Printf("Sub-zh英文hun排[-100:-90]=%s\n", Sub("zh英文hun排", -100, -90))
+	fmt.Printf("Sub-zh英文hun排[-10:-90]=%s\n", Sub("zh英文hun排", -10, -90))
+
+	// Output:
+	// Sub-[0:100]=
+	// Sub-facgbheidjk[3:9]=gbheid
+	// Sub-facgbheidjk[-50:100]=facgbheidjk
+	// Sub-facgbheidjk[-3:length]=djk
+	// Sub-facgbheidjk[-3:-1]=dj
+	// Sub-zh英文hun排[2:5]=英文h
+	// Sub-zh英文hun排[2:-1]=英文hun
+	// Sub-zh英文hun排[-100:-1]=zh英文hun
+	// Sub-zh英文hun排[-100:-90]=
+	// Sub-zh英文hun排[-10:-90]=
+}
+
+func Example_substart() {
+	fmt.Printf("SubStart-[0:]=%s\n", SubStart("", 0))
+	fmt.Printf("SubStart-[2:]=%s\n", SubStart("", 2))
+	fmt.Printf("SubStart-facgbheidjk[3:]=%s\n", SubStart("facgbheidjk", 3))
+	fmt.Printf("SubStart-facgbheidjk[-50:]=%s\n", SubStart("facgbheidjk", -50))
+	fmt.Printf("SubStart-facgbheidjk[-3:]=%s\n", SubStart("facgbheidjk", -3))
+	fmt.Printf("SubStart-zh英文hun排[3:]=%s\n", SubStart("zh英文hun排", 3))
+
+	// Output:
+	// SubStart-[0:]=
+	// SubStart-[2:]=
+	// SubStart-facgbheidjk[3:]=gbheidjk
+	// SubStart-facgbheidjk[-50:]=facgbheidjk
+	// SubStart-facgbheidjk[-3:]=djk
+	// SubStart-zh英文hun排[3:]=文hun排
+}
+
+func Example_pad() {
+
+	fmt.Printf("PadLeft=[%s]\n", PadLeftSpace("abc", 7))
+	fmt.Printf("PadLeft=[%s]\n", PadLeftChar("abc", 7, '-'))
+	fmt.Printf("PadCenter=[%s]\n", PadCenterChar("abc", 7, '-'))
+	fmt.Printf("PadCenter=[%s]\n", PadCenterChar("abcd", 7, '-'))
+
+	// Output:
+	// PadLeft=[    abc]
+	// PadLeft=[----abc]
+	// PadCenter=[--abc--]
+	// PadCenter=[-abcd--]
+}

lang/stringx/is.go

@@ -0,0 +1,53 @@
+// Copyright 2021 ByteDance Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package stringx
+
+import (
+	"unicode"
+)
+
+// IsAlpha checks if the string contains only unicode letters.
+func IsAlpha(s string) bool {
+	for _, v := range s {
+		if !unicode.IsLetter(v) {
+			return false
+		}
+	}
+	return true
+}
+
+// IsAlphanumeric checks if the string contains only Unicode letters or digits.
+func IsAlphanumeric(s string) bool {
+	for _, v := range s {
+		if !isAlphanumeric(v) {
+			return false
+		}
+	}
+	return true
+}
+
+// IsNumeric Checks if the string contains only digits. A decimal point is not a digit and returns false.
+func IsNumeric(s string) bool {
+	for _, v := range s {
+		if !unicode.IsDigit(v) {
+			return false
+		}
+	}
+	return true
+}
+
+func isAlphanumeric(v rune) bool {
+	return unicode.IsDigit(v) || unicode.IsLetter(v)
+}

lang/stringx/is_test.go

@@ -0,0 +1,37 @@
+// Copyright 2021 ByteDance Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package stringx
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIs(t *testing.T) {
+	is := assert.New(t)
+
+	is.False(IsNumeric(" bob "))
+	is.True(IsNumeric("123"))
+
+	is.False(IsAlpha("123"))
+	is.True(IsAlpha("Voa"))
+	is.True(IsAlpha("bròwn"))
+
+	is.True(IsAlphanumeric("Voa"))
+	is.True(IsAlphanumeric("123"))
+	is.True(IsAlphanumeric("v123oa"))
+	is.False(IsAlphanumeric("v123oa,"))
+}