我可以使用什么正则表达式在逗号分隔的列表中找到Nᵗʰ项？ [英] What regular expression can I use to find the Nᵗʰ entry in a comma-separated list?

问题描述

我需要一个可用于以逗号分隔的列表中找到第 N ^th 项的正则表达式。

I need a regular expression that can be used to find the N^th entry in a comma-separated list.

例如，说此列表如下：

abc,def,4322,[e-mail],3321,alpha-beta,43

...我想找到7 < sup> th 条目（ alpha-beta ）。

...and I wanted to find the value of the 7^th entry (alpha-beta).

推荐答案

我的第一个想法不是使用正则表达式，而是使用将字符串拆分为逗号数组的方法，但是由于您要使用正则表达式。

My first thought would not be to use a regular expression, but to use something that splits the string into an array on the comma, but since you asked for a regex.

大多数正则表达式允许您指定最小或最大匹配，因此类似的操作可能会起作用。

most regexes allow you to specify a minimum or maximum match, so something like this would probably work.

/（?? [[^ ＼ ＼，] * \，）{6}（[^，] *）/

这旨在匹配任意数量的字符不是逗号，然后是正好是（？：[^，] *，）{6}六倍的逗号{6} -？：说不捕获-然后匹配并捕获任何不是逗号的字符数（[^，] +）。您想使用第一个捕获组。

This is intended to match any number of character that are not a comma followed by a comma six times exactly (?:[^,]*,){6} - the ?: says to not capture - and then to match and capture any number of characters that are not a comma ([^,]+). You want to use the first capture group.

让我知道是否需要更多信息。

Let me know if you need more info.

编辑：我对上面的内容进行了编辑，以不捕获字符串的第一部分。此正则表达式可在C＃和Ruby中使用。

I edited the above to not capture the first part of the string. This regex works in C# and Ruby.

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