如何在go中反转任意数组？

Of course, one can always write a for loop. But code sharing is usually always good. So is there a way to write a method that sorts any array? Also, performance, so I'm guessing that rules out reflection.

sort.Reverse doesn't seem to work. The following will not compile:

package main

import (
    "fmt"
    "sort"
)

type A struct {
    X int
}

func main() {
x := make([]A, 0)
x = append(x, A{1})
x = append(x, A{2})
sort.Reverse(sort.IntSlice(x))
fmt.Println(x)
}

[]A is not an int slice, it's a slice of structs and you must implement a sort.Interface to describe how to sort it.

Here's a working example:

package main

import (
    "fmt"
    "sort"
)

type A struct {
    X int
}

type ByX []A

func (a ByX) Len() int           { return len(a) }
func (a ByX) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
func (a ByX) Less(i, j int) bool { return a[i].X < a[j].X }

func main() {
    x := make([]A, 0)
    x = append(x, A{1})
    x = append(x, A{2})
    sort.Sort(sort.Reverse(ByX(x)))
    fmt.Println(x)
}

Try it on the Go playground.

Alternatively, you can call sort.Slice and provide it with only the Less function:

sort.Slice(x, func(i, j int) bool { return x[i].X > x[j].X })

You should notice that the less function is different. Since we want to sort in reverse and the shorthand sort.Slice isn't compatible with sort.Reverse, we had to modify the less function to return the opposite (> instead of <).