10.字符串原理解析

a.字符串底层就是一个byte数组，所以可以和[]byte类型互相转换

b.字符串之中的字符是不能修改的,想要修改只能用byte切片来修改

  1: package main
  2: 
  3: import (
  4: 	"fmt"
  5: )
  6: 
  7: func testString(){
  8: 	var str string = "hello"
  9: 	fmt.Printf("str[0]=%c len(str)=%d\n", str[0], len(str))
 10: 	for index, val := range str {
 11: 		fmt.Printf("str[%d]=%c\n", index, val)
 12: 	}
 13: 	// 定义byte切片
 14: 	var byteSlice []byte
 15: 	byteSlice = []byte(str)
 16: 	byteSlice[0] = 'o'
 17: 	str = string(byteSlice)
 18: 	fmt.Println(str)
 19: }
 20: 
 21: func main()  {
 22: 	testString()
 23: }

c.字符串是byte字节组成,所以字符串的长度是byte字节的长度
d.rune类型用来表示utf8字符，一个rune字符由1个或多个byte组成

  1: var b rune = '中'
  2: 	str = "中文123"
  3: 	fmt.Printf("b=%c\n", b)
  4: 	var runeSlice []rune
  5: 	runeSlice = []rune(str)
  6: 	fmt.Printf("str长度=%d len(str)=%d\n", len(runeSlice), len(str))

几个关于字符串的练习：

test1:对英文字符串进行逆序

  1: func test1(){
  2: 	var str = "hello"
  3: 	// var bytes []byte = []byte(str)
  4: 	bytes := []byte(str)
  5: 	for i :=0; i < len(str)/2; i++ {
  6: 		tmp := bytes[len(str)-i-1]
  7: 		bytes[len(str)-i-1] = bytes[i]
  8: 		bytes[i] = tmp
  9: 	}
 10: 	str = string(bytes)
 11: 	fmt.Println(str)
 12: }

test2:对包含中文的字符串进行逆序

  1: func test2(){
  2: 	var str = "hello,你好"
  3: 	runes := []rune(str)
  4: 
  5: 	for i:=0; i < len(runes)/2; i++ {
  6: 		tmp := runes[len(runes)-i-1]
  7: 		runes[len(runes)-i-1] = runes[i]
  8: 		runes[i] = tmp
  9: 	}
 10: 	str = string(runes)
 11: 	fmt.Println(str)
 12: }

test3:判断一个字符串是否是回文

  1: func test3() {
  2: 	var str = "上海自来水来自海上"
  3: 	runes := []rune(str)
  4: 	for i:=0; i < len(runes)/2; i++ {
  5: 		tmp := runes[len(runes)-i-1]
  6: 		runes[len(runes)-i-1] = runes[i]
  7: 		runes[i] = tmp
  8: 	}
  9: 	str_2 := string(str)
 10: 	if str == str_2 {
 11: 		fmt.Println("yes")
 12: 	}else{
 13: 		fmt.Println("no")
 14: 	}	
 15: }