GO语言的数组array与切片slice详解

var 数组名称 [数组长度]数组类型
例：
var arr [3]int

[0 0 0]

// 第一种赋值操作
var arr = [3]int{1,2,3} //直接将值初始化，不同的类似初始化值不相同
// 第二种赋值操作
var arr [3]int  // 初始化数组变量
arr[1] = 1      // 给数组的下标赋值
// 第三种赋值操作
var arr  = [3]string{1:"one",2:"two"}
// 一般常用的就这三种，其它方式都是一些变相的操作，这里不做介绍

package main
import "fmt"
func main(){
    var arrs = [5]int{1, 2, 3, 4, 5}
    for i, v := range arrs {
        arrs[i] = v * 2
        fmt.Printf("index is %d,value is %d \n", i, arrs[i])
    }
}

index is 0,value is 2 
index is 1,value is 4 
index is 2,value is 6 
index is 3,value is 8 
index is 4,value is 10 

var arr1 = new([5]int)
var arr2 [5]int

&[0 0 0 0 0]
[0 0 0 0 0]

package main
import "fmt"
func main{
var arr_more [5][5]int
    fmt.Println(arr_more)
    for i, x := range arr_more {
        for i1, _ := range x {
            arr_more[i][i1] = i1
        }
    }
    fmt.Println(arr_more)
}

初始化数组：
[[0 0 0 0 0] [0 0 0 0 0] [0 0 0 0 0] [0 0 0 0 0] [0 0 0 0 0]]
值与索引对应
[[0 1 2 3 4] [0 1 2 3 4] [0 1 2 3 4] [0 1 2 3 4] [0 1 2 3 4]]

var 声明变量 []变量类型

package main
import "fmt"
func main{
    var arr = [5]int{1, 2, 3, 4, 5}
    var slice []int
    fmt.Printf("初始化切片默认 %d\n", slice)
    var slice1 []int = arr[:]
    fmt.Printf("切片复制数组(简写) %d\n", slice1)
    var slice2 []int = arr[0:2]
    fmt.Printf("切片获得数组0-1的下标 %d\n", slice2)
    var slice3 []int = arr[2:5]
    fmt.Printf("切片获得数组2-4的下标 %d\n", slice3)
}

初始化切片默认 []
切片复制数组(简写) [1 2 3 4 5]
切片获得数组0-1的下标 [1 2]
切片获得数组2-4的下标 [3 4 5]

var slice []int = make([]type,len,cap)
var 切片变量 []切片类型 = make([]数组类型，数组长度，最大长度) cap是可选参数

package main
import "fmt"
func main() {
    var slice1 []int = make([]int, 5)
    for i := 0; i < len(slice1); i++ {
        slice1[i] = 5 * i
        fmt.Printf("Slice at %d is %d\n", i, slice1[i])
    }
    fmt.Printf("\nThe length of slice1 is %d\n", len(slice1))
    fmt.Printf("The capacity of slice1 is %d\n", cap(slice1))
}

Slice at 0 is 0  
Slice at 1 is 5  
Slice at 2 is 10  
Slice at 3 is 15  
Slice at 4 is 20

The length of slice1 is 5  
The capacity of slice1 is 5  

package main
import "fmt"
func main(){
sl_from := []int{1, 2, 3}
    sl_to := make([]int, 10)

    n1 := copy(sl_to, sl_from)
    fmt.Println(sl_to)
    fmt.Printf("Copied %d elements\n", n1) // n == 3

    sl3 := []int{1, 2, 3}
    sl3 = append(sl3, 4, 5, 6)
    fmt.Println(sl3)
}

[1 2 3 0 0 0 0 0 0 0]
Copied 3 elements
[1 2 3 4 5 6]