Golang – 字符串常用的系统函数

package main
import (
    "fmt"
    "strconv"
    "strings"
)

func main(){

    //统计字符串的长度,按字节 len(str)
    ////golang的编码统一为utf-8 (ascii的字符(字母和数字) 占一个字节,汉字占用3个字节)
    str := "hello北" 
    fmt.Println("str len=", len(str)) // 8

    str2 := "hello北京"
    //字符串遍历,同时处理有中文的问题 r := []rune(str)
    r := []rune(str2)
    for i := 0; i < len(r); i++ {
        fmt.Printf("字符=%c\n", r[i])
    }

    //字符串转整数:    n, err := strconv.Atoi("12")
    n, err := strconv.Atoi("123")
    if err != nil {
        fmt.Println("转换错误", err)
    }else {
        fmt.Println("转成的结果是", n)
    }

    //4)整数转字符串  str = strconv.Itoa(12345)
    str = strconv.Itoa(12345)
    fmt.Printf("str=%v, str=%T\n", str, str)

    //5)字符串 转 []byte:  var bytes = []byte("hello go")
    var bytes = []byte("hello go")
    fmt.Printf("bytes=%v\n", bytes)

    //6)[]byte 转 字符串: str = string([]byte{97, 98, 99})
    str = string([]byte{97, 98, 99}) 
    fmt.Printf("str=%v\n", str)

    //10进制转 2, 8, 16进制:  str = strconv.FormatInt(123, 2),返回对应的字符串
    str = strconv.FormatInt(123, 2)
    fmt.Printf("123对应的二进制是=%v\n", str)
    str = strconv.FormatInt(123, 16)
    fmt.Printf("123对应的16进制是=%v\n", str)

    //查找子串是否在指定的字符串中: strings.Contains("seafood", "foo") //true
    b := strings.Contains("seafood", "mary")
    fmt.Printf("b=%v\n", b) 

    //统计一个字符串有几个指定的子串 : strings.Count("ceheese", "e") //4
    num := strings.Count("ceheese", "e")
    fmt.Printf("num=%v\n", num)

    //10)不区分大小写的字符串比较(==是区分字母大小写的): fmt.Println(strings.EqualFold("abc", "Abc")) // true

    b = strings.EqualFold("abc", "Abc")
    fmt.Printf("b=%v\n", b) //true

    fmt.Println("结果","abc" == "Abc") // false //区分字母大小写

    //11)返回子串在字符串第一次出现的index值,如果没有返回-1 : 
    //strings.Index("NLT_abc", "abc") // 4

    index := strings.Index("NLT_abcabcabc", "abc") // 4
    fmt.Printf("index=%v\n",index)

    //12)返回子串在字符串最后一次出现的index,
    //如没有返回-1 : strings.LastIndex("go golang", "go")

    index = strings.LastIndex("go golang", "go") //3
    fmt.Printf("index=%v\n",index)

    //将指定的子串替换成 另外一个子串: strings.Replace("go go hello", "go", "go语言", n) 
    //n可以指定你希望替换几个,如果n=-1表示全部替换

    str2 = "go go hello"
    str = strings.Replace(str2, "go", "北京", -1)
    fmt.Printf("str=%v str2=%v\n", str, str2)

    //按照指定的某个字符,为分割标识,将一个字符串拆分成字符串数组: 
    //strings.Split("hello,wrold,ok", ",")
    strArr := strings.Split("hello,wrold,ok", ",")
    for i := 0; i < len(strArr); i++ {
        fmt.Printf("str[%v]=%v\n", i, strArr[i])
    } 
    fmt.Printf("strArr=%v\n", strArr)

    //15)将字符串的字母进行大小写的转换: 
    //strings.ToLower("Go") // go strings.ToUpper("Go") // GO

    str = "goLang Hello"
    str = strings.ToLower(str) 
    str = strings.ToUpper(str) 
    fmt.Printf("str=%v\n", str) //golang hello

    //将字符串左右两边的空格去掉: strings.TrimSpace(" tn a lone gopher ntrn   ")
    str = strings.TrimSpace(" tn a lone gopher ntrn   ")
    fmt.Printf("str=%q\n", str)

    //17)将字符串左右两边指定的字符去掉 : 
    //strings.Trim("! hello! ", " !")  // ["hello"] //将左右两边 ! 和 " "去掉
    str = strings.Trim("! he!llo! ", " !")
    fmt.Printf("str=%q\n", str)

    //20)判断字符串是否以指定的字符串开头: 
    //strings.HasPrefix("ftp://192.168.10.1", "ftp") // true

    b = strings.HasPrefix("ftp://192.168.10.1", "hsp") //true
    fmt.Printf("b=%v\n", b)
}
转载请注明出处,谢谢!
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