为什么Golang在我的for循环中没有正确迭代范围? [英] Why golang don't iterate correctly in my for loop with range?

问题描述

我很困惑为什么下面的代码不能打印出迭代值.

I am confused why the following code does not print out iterated value.

test:= []int{0,1,2,3,4}
for i,v := range test{
  go func(){
    fmt.Println(i,v)
  }
}

我认为它应该打印出来

0 0
1 1
2 2
3 3 
4 4

但是，它打印出来了

4 4
4 4
4 4
4 4
4 4

推荐答案

您的goroutine不会捕获变量 i 和 v 的当前值，而是引用变量本身.在这种情况下，直到for循环完成时，才对5个生成的goroutine进行调度，因此全部打印出 i 和 v 的最后一个值.

Your goroutines don't capture the current value of the variables i and v, but rather they reference the variables themselves. In this case, the 5 spawned goroutines did not get scheduled until the for loop finished, so all printed out the last values of i and v.

如果您想捕获古丁香精的某些变量的当前值，则可以修改代码以读取如下内容:

If you want to capture the current values of some variables for the gouroutine, you could modify the code to read something like the following:

go func(i, v int){
    fmt.Println(i,v)
}(i, v)

现在，每个鱼肉例程都拥有自己的变量副本，这些副本保存着生成时的值.

Now each gouroutine has its own copy of the variables holding the value at the time it was spawned.

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