使用正则表达式查找数字的第n次出现 [英] Finding the nth occurrence of a number using regex

问题描述

我正在尝试编写一个正则表达式，它可以找到第n个出现的数字匹配项（其中N是可以在for循环中递增的数字）。我可以让正则表达式成功匹配一个数字，但不能使其与序列中的特定数字匹配。我使用的正则表达式是（[[0-9] +）{2} 。

I am trying to write a regex that can find the nth occurrence of a number match (where N is a number that can increment in a for loop). I can get the regex to successfully match a number, but I can't get it to match a specific number in the sequence. The regex I used is ([0-9]+){2}.

我要尝试的操作要做的就是从一个字符串中选出数字：Red，12，Green，5，Blue，6

What I am trying to do is pick out the number out of a string like: Red,12,Green,5,Blue,6

使用可以提取的正则表达式，然后是12、2 ，然后是3。我希望正则表达式的 {n} 部分可以完成此操作，但是例如当我将该数字设置为2而不是选择数字5时如预期的那样，它选择了12中的2，当我将数字设置为3时，它根本找不到匹配项。谁能提供我做错事情的任何见解？

Using a regex that can pick out, 12 then, 2, then 3. I was hoping the {n} part of the regex could accomplish this, but when I set that number to 2 for instance, instead of picking out the number 5 as expected, it picks up the 2 in 12, and when I set the number to 3, it is unable to find a match at all. Could anyone provide any insight into what I am doing wrong?

推荐答案

您可以使用此正则表达式选择 N 个数字：

You can use this regex to pick Nth number:

(?:\D*(\d+)){2}

将 2 替换为您想要的任何数字。您的电话号码在捕获的＃1组中可用

Replace 2 by any number you want. Your number is available in captured group #1

• \D 与任何非-digit


• \d 匹配数字

• \D matches any non-digit
• \d matches a digit

RegEx演示

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