go语言（4）

// 声明
var <name> map[keyType]valueType
var a map[int]string
var a map[string]string
var a map[int]map[int]string

// 声明不会分配内存 每个map需要使用make进行初始化
a = make(map[int]string)

// 当map的value为map时，每个map都需要初始化
var student map[int]map[string]string
student = make(map[int]map[string]string)
student[0] = make(map[string]string,3)
student[0][name] = 'guozijing'
student[0][sex] = 'male'
student[0][address] = 'beijing'

student[1] = make(map[string]string,3)

// map的删除
delete(name,key)

// 删除一整个map 遍历删除 或者重新初始化
name = make(map[int]string)

// map的查找
var , ok := name[key]
if ok {
    fmt.Println('ok')
} else {
    fmt.Println('no')
}

// map的遍历
var student map[int]map[string]string
student = make(map[int]map[string]string)
student[0] = make(map[string]string,3)
student[0][name] = 'guozijing'
student[0][sex] = 'male'
student[0][address] = 'beijing'

student[1] = make(map[string]string,3)
student[1][name] = 'guozijing'
student[1][sex] = 'male'
student[1][address] = 'beijing'

for k1,v1 := range student {
    for k2,v2 := range v2 {
        fmt.Println('%vt %vt %vn', k1, k2, v2)
    }
}

// map的切片
package main
import "fmt"

func main() {
    var student []map[string]string
    student = make([]map[string]string, 2)
    if student[0] == nil {
        student[0] = make(map[string]string,2)
        student[0]['name'] = 'guozijing'
        student[0]['sex'] = 'male'
    }
    if student[1] == nil {
        student[1] = make(map[string]string)
        student[1]['name'] = 'guojingfeng'
        student[1]['sex'] = 'male'
    }
    // append
    studentA := map[string]string {
        'name' : 'Jason',
        'sex' : 'male'
    }
    append(student, studentA)
    fmt.Println(student)
}

// map按照key排序输出value
package main
import "fmt"

func main() {
    m := make(map[int]int, 10)
    m[1] = 12
    m[10] = 20
    m[3] = 21
    m[7] = 12

    var key []int
    for k, _:= range m {
        append(key, k)
    }
    sort.Ints(key)

    for _, k := range key {
        fmt.Println(m[key])
    }
}