GO语言基本类型String和Slice,Map操作详解

import ("fmt")
func main() {  
    name := "Hello World" //声明一个值为 Hello World的字符串变量 name
    fmt.Println(name)
}

str1 := "hello world"
fmt.Println(len(str1)) // 11

str := "hello"
for i := 0; i < len(str); i++ {
	fmt.Println(i,str[i])
}

str := "hello"
for i,ch := range str {
	fmt.Println(i,ch)
}

num := 12
fmt.Printf("%T \n", string(num)      // "12"  string

str1 := "hello "
str2 := " world"
//创建字节缓冲
var stringBuilder strings.Builder
//把字符串写入缓冲
stringBuilder.WriteString(str1)
stringBuilder.WriteString(str2)
//将缓冲以字符串形式输出
fmt.Println(stringBuilder.String())

//查找s在字符串str中的索引
Index(str, s string) int 
//判断str是否包含s
Contains(str, s string) bool
//通过字符串str连接切片 s
Join(s []string, str string) string
//替换字符串str中old字符串为new字符串，n表示替换的次数，小于0全部替换
Replace(str,old,new string,n int) string

var identifier []type

var slice1 []type = make([]type, len)
也可以简写为
slice1 := make([]type, len)

func main() {
   
   numbers := []int{0,1,2,3,4,5,6,7,8}   
   printSlice(numbers)
   
   fmt.Println("numbers ==", numbers)
   
   fmt.Println("numbers[1:4] ==", numbers[1:4])
   
   fmt.Println("numbers[:3] ==", numbers[:3])
}
func printSlice(x []int){
   fmt.Printf("len=%d cap=%d slice=%v\n",len(x),cap(x),x)
}
打印结果：
len=9 cap=9 slice=[0 1 2 3 4 5 6 7 8]
numbers == [0 1 2 3 4 5 6 7 8]
numbers[1:4] == [1 2 3]
numbers[:3] == [0 1 2]

// 声明一个map类型，[]内的类型指任意可以进行比较的类型 int指值类型
m := map[string]int{"a":1,"b":2}
fmt.Print(m["a"])

func main() {
   var countryCapitalMap map[string]string
   
   countryCapitalMap = make(map[string]string)
   
   countryCapitalMap["France"] = "Paris"
   countryCapitalMap["Italy"] = "Rome"
   countryCapitalMap["Japan"] = "Tokyo"
   countryCapitalMap["India"] = "New Delhi"
   
   for country := range countryCapitalMap {
      fmt.Println("Capital of",country,"is",countryCapitalMap[country])
   }