go语言string函数的使用

package main

import (
   "fmt"
   "strconv"
   "strings"
)

func main() {
   //1
   str := "hello杯" //goland统一为utf-8（字母数字占一个字节，汉字占3个字节）
   fmt.Println(len(str))
   //len是按字节返回的，不是按字符
   //2
   str2 := "hello被禁"
   r := []rune(str2)
   for i := 0; i < len(r); i++ { //处理有中文，转切片
      fmt.Printf("str2:%c", r[i])
   }
   //3 string转int
   n, err := strconv.Atoi("123")
   if err != nil {
      fmt.Printf("转换错误")
   } else {
      fmt.Println("结果：", n)
   }
   //4 int转string
   str = strconv.Itoa(123)
   fmt.Printf("%v,%T", str, str)
   //5  string转byte
   var bytes = []byte("hello,go") //转字节
   fmt.Printf("%v\n", bytes)
   //6 byte转string
   str = string([]byte{97, 98, 99})
   fmt.Printf("%v\n%T", str, str)
   //7
   str = strconv.FormatInt(123, 2) //int转2进制
   fmt.Println(str)
   str = strconv.FormatInt(123, 16) //int转16进制
   fmt.Printf(str)
   //8 匹配
   b := strings.Contains("setfoot", "foot")
   fmt.Printf("%v", b) //true
   //9 统计字符传个数
   num := strings.Count("ceheess", "e") //3
   fmt.Printf("%v", num)
   //10  不区分大小写判断
   b = strings.EqualFold("abc", "ABC") //true
   fmt.Printf("%v", b)                 //不区分大小写
   //区分大小写判断
   fmt.Println("abc" == "ABC") //区分大小写
   //11 //找到第一次下标
   index := strings.Index("abcdefadef", "def")
   fmt.Printf("%v\n", index)
   //12判断字符串最后一次出现的位置
   index = strings.LastIndex("abcgewfecgs", "cg")
   fmt.Printf("%v\n", index)
   //13替换字符串,-1为全部替换,值传递
   str = strings.Replace("go go hello", "go", "java", -1)
   fmt.Printf("%v\n", str)
   //14按要求分割数组,值拷贝
   strArr := strings.Split("hello,ok,world", ",")
   fmt.Printf("%v\n", strArr)
   for i := 0; i < len(strArr); i++ {
      fmt.Printf("str[%v]=%v\n", i, strArr[i])
   }
   //15大小写转换
   str = "goLand Hello"
   str = strings.ToLower(str) //全部转小写
   str = strings.ToUpper(str) //全部转大写
   fmt.Printf("%v\n", str)

   //16去掉左右空格
   str = strings.TrimSpace("    tn  f fssd fs  ")
   fmt.Printf("%q\n", str)
   //17指定去左右字符
   str = strings.Trim("! he!llo! ", " ")
   str = strings.TrimLeft(" ! he!llo! ", " ")
   str = strings.TrimRight(" ! he!llo! ", " ")
   fmt.Printf("%q\n", str)
   //20判断字符串是否指定开头：
   b = strings.HasPrefix("ftp://1542.434.232.423", "ftp")
   fmt.Printf("%v\n", b)
   b = strings.HasSuffix("ftp://1542.434.232.423", "ftp")
   fmt.Printf("%v\n", b)
   
}