package main

import "fmt"

func main()  {

   testAppend()
   testCopy()
   testDelete()
}

func testAppend()  {

   var sl = make([]int,2)
   sl[0] = 1
   sl[1] = 2
   fmt.Println(len(sl))
   fmt.Println(cap(sl))
   sl = append(sl, 3)
   //sl = append(sl, 4)
   fmt.Println(sl)
   fmt.Println(len(sl))
   fmt.Println(cap(sl))
}

func testCopy()  {
   var sl1 = make([]string,3)
   var sl2 = make([]string,2)

   sl1[0] = "a"
   sl1[1] = "b"
   sl1[2] = "e"
   sl2[0] = "c"
   sl2[1] = "d"

   copy(sl1,sl2)
   fmt.Println(sl1)

}

func testDelete()  {
   var sl = make(map[int]int ,2)
   sl[1] = 1
   sl[2] = 2
   sl[3] = 3

   delete(sl, 2)
   fmt.Println(sl)
}

结果如下

GOROOT=/usr/local/go #gosetup
GOPATH=/www/gopath #gosetup
/usr/local/go/bin/go build -i -o /private/var/folders/fc/4txmmczj6q92p6058h3w7t_80000gn/T/___go_build_main_go__2_ /www/go/learn/main.go #gosetup
/private/var/folders/fc/4txmmczj6q92p6058h3w7t_80000gn/T/___go_build_main_go__2_ #gosetup
2
2
[1 2 3]
3
4
[c d e]
map[1:1 3:3]

Process finished with exit code 0