Seq.iter vs for-有什么区别? [英] Seq.iter vs for - what difference?

问题描述

我可以做到

for event in linq.Deltas do

或者我可以做

linq.Deltas |> Seq.iter(fun event ->

所以我不确定是否相同.如果那不一样，我想知道区别.我不知道该使用什么:iter或for.

So I'm not sure if that is the same. If that is not the same I want to know the difference. I don't know what to use: iter or for.

已添加-因此，如果这是选择的问题，那么我更愿意在顶层使用iter，而for用于闭包

added - so if that is the matter of choice I prefer to use iter on a top level and for is for closures

稍后再添加-看起来iter是map + ignore-这是使用命令式忽略词的一种方式.所以看起来就像是功能方式...

added some later - looking like iter is map + ignore - it's the way to run from using imperative ignore word. So it's looking like functional way ...

推荐答案

您可以从for循环的主体中修改可变变量.您不能从闭包中做到这一点，这意味着您不能使用iter做到这一点. (注意:我说的是在for/iter外部声明的可变变量.可以访问局部可变变量.)

You can modify mutable variables from the body of a for loop. You can't do that from a closure, which implies you can't do that using iter. (Note: I'm talking about mutable variables declared outside of the for / iter. Local mutable variables are accessible.)

考虑到iter的作用是要产生一些副作用，所以区别可能很重要.

Considering that the point of iter is to perform some side effect, the difference can be important.

我个人很少使用iter，因为我发现for更清楚.

I personally seldom use iter, as I find for to be clearer.

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