去 WaitGroup 不明显的行为

Question

这个问题在这里已经有了答案:





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2年前关闭。




我不明白为什么这个代码返回

三
三
三

package main

import (
    "fmt"
    "sync"
)

func main() {
    wg := sync.WaitGroup{}
    data := []string{"one", "two", "three"}
    for _, v := range data {
        wg.Add(1)
        go func() {
            fmt.Println(v)
            wg.Done()
        }()
    }
    wg.Wait()
}

请解释任何人

Answer 1

添加 v := v作为循环中的第一行。

Reference :

This is because each iteration of the loop uses the same instance of the variable v[...]