[GO] delete range map

package main

import (
    "fmt"
)

func main() {
    mymap := make(map[int]string)

    mymap[1] = "test1"
    mymap[2] = "test2"
    mymap[3] = "test3"
    mymap[4] = "test4"

    fmt.Println(mymap)

    for k, v := range mymap {
        fmt.Println(k, v)
    }

    for k := range mymap {
        if k == 1 {
            delete(mymap, k) //如果C++这么写的话，迭代器会出问题。
        }
    }

    fmt.Println(mymap)
}

package main

import "fmt"

func testSlice() {
    a := []int{1, 2, 3, 4, 5}

    fmt.Println(a)
    first := true
    for i, userID := range a {
        fmt.Println(i, userID)
        if first {
            a = a[:2]
        }
        fmt.Println(a)
    }
}

func main() {
    testSlice()
}

package main

import "fmt"

func testDump() {
    a := []int{2, 2}

    fmt.Println(a)
    for i, userID := range a {
        fmt.Println(i, userID)
        if userID == 2 {
            a = append(a[:i], a[i+1:]...)
        }
        fmt.Println(a)
    }
}

func main() {
    testDump()
}