golang 数组与切片【基础操作】

package main

import "fmt"

func main() {
    var team = [...]string{"hammer", "soldier", "mum"}
    fmt.Println(team) //[hammer soldier mum]

    for k, v := range team {
        fmt.Println(k, v)
    }
    //0 hammer
    //1 soldier
    //2 mum

    a := 2
    b := 28
    c := a + b
    fmt.Println(c) // 30

    var build [30]int
    for i := 0; i < 30; i++ { //0 ~ 29
        build[i] = i + 1
    }

    //切片全部整体
    fmt.Println(build)
    //[1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30]
    fmt.Println(build[:])           //与切片本身等效
    fmt.Println(build[:len(build)]) //与切片本身等效
    fmt.Println(build[:30])         //与切片本身等效

    //部分
    fmt.Println(build[5:10]) //[6 7 8 9 10]
    fmt.Println(build[18:])  //[19 20 21 22 23 24 25 26 27 28 29 30]
    fmt.Println(build[:2])   //[1 2]
    fmt.Println(build[0:0])  //[] 空切片，一般用于切片复位
    fmt.Println(build[0:1])  //[1]
    fmt.Println(build[30:])  //[]

    var numbers []int
    for i := 0; i < 10; i++ {
        numbers = append(numbers, i)
        fmt.Printf("len: %d cap:%d pointer:%p \n", len(numbers), cap(numbers), numbers)
    }
    /*
       len: 1 cap:1 pointer:0xc000016400
       len: 2 cap:2 pointer:0xc000016410

       len: 3 cap:4 pointer:0xc000014120
       len: 4 cap:4 pointer:0xc000014120

       len: 5 cap:8 pointer:0xc00001a100
       len: 6 cap:8 pointer:0xc00001a100
       len: 7 cap:8 pointer:0xc00001a100
       len: 8 cap:8 pointer:0xc00001a100

       len: 9 cap:16 pointer:0xc000102080
       len: 10 cap:16 pointer:0xc000102080
    */

    //  切片复制
    //设置元素数量
    const count = 10
    //预分配足够多的元素切片
    srcData := make([]int, count)

    //将切片赋值
    for i := 0; i < count; i++ {
        srcData[i] = i
    }

    //引用切片数据
    refData := srcData

    //预分配足够多的元素切片
    copyData := make([]int, count)

    //将数据分配到新的切片空间copyData中
    copy(copyData, srcData)
    fmt.Println(copyData, refData) //[0 1 2 3 4 5 6 7 8 9] [0 1 2 3 4 5 6 7 8 9]

    //修改原始数据的第一个元素
    srcData[0] = 999

    //打印复制切片的第一个和最后一个元素;复制数据不变，原始数据改变
    fmt.Println(copyData[0], copyData[count-1], copyData, refData)
    //0 9 [0 1 2 3 4 5 6 7 8 9] [999 1 2 3 4 5 6 7 8 9]

    copy(copyData, srcData[4:6])
    fmt.Println(copyData, refData,srcData)
    //[4 5 2 3 4 5 6 7 8 9] [999 1 2 3 4 5 6 7 8 9][999 1 2 3 4 5 6 7 8 9]

    for i := 0; i < 5; i++ {
        fmt.Printf("i= %d  v= %d \n",i,copyData[i])// 4 5 2 3 4 %
    }

    //删除元素
    seq:=[]string{"a","b","c","d","e","f"}
    //指定删除位置
    delIndex:=2
    //查看删除前和之后的元素
    fmt.Println(seq[:delIndex],seq[delIndex+1:])
//[a b] [d e f]
    //将删除前后的元素连接起来
    seq=append(seq[:delIndex],seq[delIndex+1:]...)
    fmt.Println(seq)//  [a b d e f]

}