1 package main 2  3 import "fmt" 4  5 //Map 6 //创建：make(map[string]int) 7 //获取元素： m[key] 8 //key不存在时，获得value类型的初始值 9 //用value， ok:= m[key]来判断是否存在key10 //delete删除元素11 //用range遍历key，或者遍历key，value对12 //不保证遍历顺序，如需顺序，需手动对key排序13 //用len获得元素个数14 //map使用哈希表，必须可以比较相等15 //除了slice， map, function的内建类型都可以作为key16 //struct类型不包含上述字段也可以作为key17 18 func main() {19     //创建map20     m := map[string] string {21         "name": "ccmouse" ,22         "course": "golang",23         "site": "imooc",24         "quality": "notbad",25     }26     fmt.Println(m) //map[course:golang site:imooc quality:notbad name:ccmouse]27 28     m2 := make( map[string]int)29     fmt.Println(m2)  //map[]  m2 == empty map30 31     var m3 map[string]int32     fmt.Println(m3)  //map[]  m3 == nil33 34     //map的遍历35     for k, v := range m{36         fmt.Println(k, v)   //name ccmouse //hash map输出无序37                             //course golang38                             //site imooc39                             //quality notbad40     }41 42     //map取值43     courseName, ok := m["course"]44     fmt.Println(courseName, ok)  //golang true45 46     if causeName, ok:= m["cause"]; ok{  //判断值存不存在47         fmt.Println(causeName)48     }else{49         fmt.Println("Key does not exist")   //Key does not exist50     }51 52     //删除元素53     name, ok := m["name"]54     fmt.Println(name, ok)  //ccmouse true55     delete(m, "name")56     name, ok = m["name"]57     fmt.Println(name, ok)  // false58 }