表达式使用的特殊构造 [英] Special construct of expression use

问题描述

使用If-Then-Else Conditionalsa> 在正则表达式中，我想知道尝试将 many 构造操纵成多个匹配的单个表达式的可能结果.

With the construct of using If-Then-Else Conditionals in regular expressions, I would like to know the possible outcome of trying to manipulate many constructs into a single expression for multiple matches.

让我们以下面这个例子为例.

Let's take this example below.

foo(bar)?(?(1)baz|quz)

现在与一个匹配前一个条件的表达式组合，然后我们用以下条件添加到前一个条件..

Now being combined with an expression, which matches the previous conditions and then we add on to the previous with the following conditions..

foo(bar)?(?(1)baz|quz)|(?(?=.*baz)bar|foo)

我主要是问您是否应该以这种方式构建正则表达式，以及您需要以这种方式使用它的目的是什么?

Mainly I am asking should you construct a regular expression in this way, and what would ever be the purpose that you would need to use it in this way?

推荐答案

你应该用这种方式构造一个正则表达式吗?曾经是您需要以这种方式使用它的目的吗?

should you construct a regular expression in this way, and what would ever be the purpose that you would need to use it in this way?

在这种情况下，并且可能在大多数情况下，我会说不".

In this case, and probably most cases, I would say "no".

我经常发现条件可以重写为环视或在交替中简化.

I often find that conditionals can be rewritten as lookarounds or simplified within alternations.

例如，在我看来，你提供的正则表达式，

For instance, it seems to me that the regex you supplied,

foo(bar)?(?(1)baz|quz)|(?(?=.*baz)bar|foo)

可以替换为更清晰的

bar(?=.*baz)|foo(?:quz|barbaz)?

这给了我们两个简单的匹配路径.

which gives us two simple match paths.

但是您发布问题已经六个月了.在这段时间里，回答了很多关于 SO 的问题，你有没有觉得需要这样的建设?

But it's been six months since you posted the question. During this time, answering a great many questions on SO, have you ever felt the need for that kind of construction?

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