Golang解压变量参数

解压变量参数

package main

import "fmt"

func run(a, b string, list ...int) {
    fmt.Println(list)
    for i, e := range list {
        fmt.Println(i, e)
    }
}

func call(list ...int) {
    fmt.Println(list)
    var x, y string
    run(x, y, list...) // use "list..." is allowed
}

func main() {
    a := []int{1, 2, 3}
    fmt.Println(a)
    call(a...)
}

游乐场: https://play.golang.org/p/NI0L-nVVUxm

输出:

[1 2 3]
[1 2 3]
[1 2 3]
0 1
1 2
2 3

只有当传递给Variadic函数的切片是 多变的论点。因此,不能将单个参数和展开的切片合并到一个变量参数中。当您使用扩展时,函数接收“expanded”切片本身作为其可变参数-语义糖可能会令人困惑,因为这些调用是不等价的:

foo := []string{"alpha","beta"}
bar(foo...) // bar receives the foo slice as its variadic parameter
bar(foo[0], foo[1]) // bar receives a new slice with these elements copied to it

你可以找到更多细节 in the spec

https://play.golang.org/p/gZnMALrM4Uh

package main

import (
    "fmt"
)

func run(a, b string, list ...int) {
fmt.Println(list)
}

func call(list ...int) {
    run("x", "y", list...) // ok
}

func main() {
    a := []int{1, 2, 3}
    call(a...)
}