Golang strings 包常用字符串操作函数

目录

1. func Contains

2. func HasPrefix

3. func HasSuffix

4. func Replace

5. func Split

6. func ToLower

7. func ToUpper

8. func Repeat

---

在编写代码的时候最常用到的就是字符串了，本篇文章将结合实例对常用的字符串操作函数进行介绍。

1. func Contains

func Contains(s, substr string) bool

判断 substr 是否是 s 的子串，例如：

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.Contains("Linux", "in"))
	fmt.Println(strings.Contains("Linux", "Unix"))
	fmt.Println(strings.Contains("Linux", ""))
	fmt.Println(strings.Contains("", ""))
}

输出：

true
false
true
true

2. func HasPrefix

func HasPrefix(s, prefix string) bool

字符串 s 是否以 prefix 为开头，例如：

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.HasPrefix("Linux", "Lin"))
	fmt.Println(strings.HasPrefix("Linux", "in"))
	fmt.Println(strings.HasPrefix("Linux", ""))
}

输出：

true
false
true

3. func HasSuffix

func HasSuffix(s, suffix string) bool

判断字符串 s 是否以 suffix 结尾，例如：

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.HasSuffix("Linux", "nux"))
	fmt.Println(strings.HasSuffix("Linux", "ix"))
	fmt.Println(strings.HasSuffix("Linux", ""))
}

输出为：

true
false
true

4. func Replace

func Replace(s, old, new string, n int) string

返回 s 中前 n 个不重复的 old 子串替换为 new 子串的新字符串，如果 n < 0 ，则替换所有 old 子串，例如：

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.Replace("Linux is very very very good!", "very", "much", 2))
	fmt.Println(strings.Replace("Linux is very very very good!", "very", "much", -1))
}

输出为：

Linux is much much very good!
Linux is much much much good!

5. func Split

func Split(s, sep string) []string

返回将字符串 s 按 sep子串分割的字符串切片，sep 为空字符串时，将 s 分割为每一个 unicode 码值的字符串切片。例如：

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.Split("Linux, Unix, Windows, Android", ", "))
	fmt.Println(strings.Split(" Linux is very very very good! ", " "))
}

输出为：返回的是字符串数组。

[Linux Unix Windows Android]
[ Linux is very very very good! ]

6. func ToLower

func ToLower(s string) string

返回字符串 s 中字母转小写的拷贝，例如：

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.ToLower("Linux, Unix, Windows, Android"))
	fmt.Println(strings.ToLower(" Linux is very very very good! "))
}

输出为：

linux, unix, windows, android
 linux is very very very good!

7. func ToUpper

func ToUpper(s string) string

返回字符串 s 中字母转大写的拷贝，例如：

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.ToUpper("Linux, Unix, Windows, Android"))
	fmt.Println(strings.ToUpper(" Linux is very very very good! "))
}

输出为：

LINUX, UNIX, WINDOWS, ANDROID
 LINUX IS VERY VERY VERY GOOD! 

8. func Repeat

func Repeat(s string, count int) string

返回 count 个字符串 s 相连接的字符串，如果 count 为负数 或（len * s * count）的结果溢出，则报 panic 异常。例如：

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.Repeat("Linux", 6))
	fmt.Println(strings.Repeat("Linux", 0))
	fmt.Println(strings.Repeat("Linux", -1))
}

输出为：

LinuxLinuxLinuxLinuxLinuxLinux

panic: strings: negative Repeat count

goroutine 1 [running]:
strings.Repeat(0x4bcf3d, 0x5, 0xffffffffffffffff, 0x1, 0x1)
        /usr/local/go/src/strings/strings.go:529 +0x5e5
main.main()
        /root/goProject/src/test/main.go:11 +0x167

参考链接：

https://golang.org/pkg/strings/