Go中map的操作與使用(增刪改查)
阿新 • • 發佈：2018-10-05
map aaa 使用 () fun true 增刪改 println 值傳遞
// code_014_map_operator project main.go
package main
import (
"fmt"
)
func DeleteMap(m map[int]string, key int) {
delete(m, key)
for k, v := range m {
fmt.Printf("len(m)=%d, %d ----> %s\n", len(m), k, v)
}
}
func main() {
//賦值-->修改和追加
m1 := map[int]string{1: "ck_god", 2: "god_girl"}
m1[1] = "xxx"
m1[3] = "lily" //追加，go底層自動為map分配空間
fmt.Println(m1)
m2 := make(map[int]string, 10)
m2[0] = "aaa"
m2[1] = "bbb"
fmt.Println(m2)
fmt.Println(m2[0], m2[1])
fmt.Println("")
//遍歷
m3 := map[int]string{1: "ck_god", 2: "god_girl"}
for k, v := range m3 {
fmt.Printf("%d--->>>%s\n", k, v)
}
for k := range m3 {
fmt.Printf("%d--->%s\n", k, m3[k])
}
fmt.Println("")
//獲取map的值
value, ok := m3[1]
fmt.Println("value = ", value, ", ok = ", ok)
value2, ok2 := m3[3]
fmt.Println("value2 = ", value2, ", ok2 = ", ok2)
fmt.Println("")
//刪除
m4 := map[int]string{1: "ck_god", 2: "god_girl"}
delete(m4, 2) //刪除key值為2的map
for k, v := range m4 {
fmt.Printf("%d--->%s\n", k, v)
}
fmt.Println("")
//map作為參數傳遞
//在函數間傳遞映射並不會制造出該映射的一個副本，不是值傳遞，而是引用傳遞：
m := map[int]string{1: "ck_god", 2: "god_girl", 3: "girl_angle"}
DeleteMap(m, 3)
for k, v := range m {
fmt.Printf("len(m)=%d, %d ----> %s\n", len(m), k, v)
}
}
執行結果如下：
map[1:xxx 2:god_girl 3:lily] map[1:bbb 0:aaa] aaa bbb 1--->>>ck_god 2--->>>god_girl 2--->god_girl 1--->ck_god value = ck_god , ok = true value2 = , ok2 = false 1--->ck_god len(m)=2, 1 ----> ck_god len(m)=2, 2 ----> god_girl len(m)=2, 1 ----> ck_god len(m)=2, 2 ----> god_girl
Go中map的操作與使用(增刪改查)