在GoLang中排序对

Question

I know how to sort key/value with data type:

map[1:a 2:c 0:b]

using sort package of GoLang. How can I sort a Pair like the following:

[{c 2} {a 1} {b 0}]

I want the whole pair to be sorted either according to key or value? End result:

[{a 1} {b 0} {c 2}]

this is sorted according to keys. Below is sorted according to values:

[{b 0} {a 1} {c 2}]

Answer 1

You could implement Len, Swap and Less for a custom type. An example is given here: https://gobyexample.com/sorting-by-functions

Here's how you could sort by key for your example: http://play.golang.org/p/i6-e4I7vih

import (
    "fmt"
    "sort"
)

type Pair struct {
    Key   string
    Value int
}

type ByKey []Pair

func (s ByKey) Len() int {
    return len(s)
}

func (s ByKey) Swap(i, j int) {
    s[i], s[j] = s[j], s[i]
}

func (s ByKey) Less(i, j int) bool {
    return s[i].Key < s[j].Key
}

func main() {
    pairs := []Pair{{"a", 1}, {"b", 0}, {"c", 2}}
    // Sort by Key
    sort.Sort(ByKey(pairs))
    fmt.Println(pairs) // [{a 1} {b 0} {c 2}]
}