python – 为什么Go的地图迭代顺序在打印时会有所不同？

package main

import "fmt"

func main(){
    sample := map[string]string{
    "key1":"value1","key2":"value2","key3":"value3",}
    for i := 0;i<3;i++{
        fmt.Println(sample)
    }
}

上面的代码只打印了一个map [string]字符串三次.

我希望它是一个固定的输出,但它显示如下：

map[key3:value3 key2:value2 key1:value1]
map[key1:value1 key3:value3 key2:value2]
map[key2:value2 key1:value1 key3:value3]

它有所不同！

而在python中：

#!/bin/env python
#encoding=utf8

sample = {
    "key1":"value1",}
for i in range(3):
    print sample

输出：

{'key3': 'value3','key2': 'value2','key1': 'value1'}
{'key3': 'value3','key1': 'value1'}`