go - 它不是以要求的格式打印，而是以无序格式打印

Question

package main

import (
  "fmt"
  "bufio"
  "os"
  "strconv"
)
func main() {
 mp := make(map[int]string)//make a mapping
 in := bufio.NewScanner(os.Stdin)
 fmt.Println("Limit and Enter Strings")
 in.Scan()
 n := in.Text()
 num, err := strconv.Atoi(n)
 fmt.Println(err)
 for i:=0; i<=num;i++ {
   in.Scan()
   mp[i] = in.Text()
 }
 fmt.Println(mp)
}
/* Output Limit and Enter Strings
5
<nil>
one
two
three
four
five
six
map[3:four 4:five 5:six 0:one 1:two 2:three]*/

该程序用于从 int 到 string 的映射。当我以顺序格式输入数字时，它会以错误的顺序打印映射。

Answer 1

Go provides a built-in map type that implements a hash table.

When iterating over a map with a range loop, the iteration order is not specified and is not guaranteed to be the same from one iteration to the next. Since Go 1 the runtime randomizes map iteration order, as programmers relied on the stable iteration order of the previous implementation. If you require a stable iteration order you must maintain a separate data structure that specifies that order. This example uses a separate sorted slice of keys to print a map[int]string in key order:

导入“排序”

var m map[int]string
var keys []int
for k := range m {
    keys = append(keys, k)
}
sort.Ints(keys)
for _, k := range keys {
    fmt.Println("Key:", k, "Value:", m[k])
}

链接:https://blog.golang.org/go-maps-in-action