Go简单排序

写代码的时候发现需要对map[int64]int64排序，golang中sort包来解决这个问题，下面是从网上找的2个例子，备忘下。

例子一：

package main
import (
    "fmt"
    "sort"
)
func main() 
    m := map[string]string{"b": "15", "z": "123123", "x": "sdf", "a": "12"}
    mk := make([]string, len(m))
    i := 0
    for k, _ := range m {
        mk[i] = k
        i++
    }
    sort.SortStrings(mk)
    fmt.Println(mk)
}

例子二：

// A data structure to hold a key/value pair.
type Pair struct {
    Key   string
    Value int
}

// A slice of Pairs that implements sort.Interface to sort by Value.
type PairList []Pair

func (p PairList) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
func (p PairList) Len() int           { return len(p) }
func (p PairList) Less(i, j int) bool { return p[i].Value < p[j].Value }

// A function to turn a map into a PairList, then sort and return it.
func sortMapByValue(m map[string]int) PairList {
    p := make(PairList, len(m))
    i := 0
    for k, v := range m {
        p[i] = Pair{k, v}
    }
    sort.Sort(p)
    return p
}