你能以相反的顺序运行foreach吗？ [英] Can you run a foreach in reverse order?

问题描述

是否可以执行类似于STL迭代器的操作，即以相反的顺序执行$ ​​b $ ba foreach循环？


谢谢，

Fabio

Is it possible to do something similar to the STL iterators, i.e. to execute
a foreach loop in reverse order?

Thanks,
Fabio

推荐答案

在这里讨论......

http://groups.google.com/group/微... e1478a9703dd2d

Discussed here......

http://groups.google.com/group/micro...e1478a9703dd2d

Fabio，

Fabio,

是否有可能做类似的事情STL迭代器，即以相反的顺序执行foreach循环？

Is it possible to do something similar to the STL iterators, i.e. to
execute a foreach loop in reverse order?

在执行
之前，可以简单地颠倒集合的顺序
foreach循环。我知道这是第二好的选择。然而，它会起作用。


问候，


兰迪

One could simply reverse the order of the collection before executing the
foreach loop. I know that is a second-best options. However, it will work.

Regards,

Randy

Fabio Cannizzo < FC ***************** @ london.edu>写道：

Fabio Cannizzo <fc*****************@london.edu> wrote:

是否有可能做类似于STL迭代器的事情，即以相反的顺序执行一个foreach循环？

Is it possible to do something similar to the STL iterators, i.e. to execute
a foreach loop in reverse order?

否 - 并不是每个迭代器都能支持这种行为

无论如何。考虑一个基于来自

a网络的流的foreach - 你必须等待才能找到流的结尾（如果那个

曾经发生过）在你开始回馈数字之前。


另一个例子 - 考虑一个产生素数的迭代器，在

顺序中。反转迭代器会做什么？


-

Jon Skeet - < sk *** @ pobox.com>
http://www.pobox.com/~skeet 博客： http://www.msmvps.com/jon.skeet

如果回复小组，请不要给我发邮件

No - and not every iterator would be able to support that behaviour
anyway. Consider a foreach which was based off a stream coming in from
a network - you''d have to wait to find the end of the stream (if that
ever happened) before you could start giving back numbers.

Another example - consider an iterator which yielded prime numbers, in
order. What would a reversed iterator do?

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

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