在哪个行号找到正则表达式匹配？ [英] On Which Line Number Was the Regex Match Found?

问题描述

我想使用正则表达式搜索 .java 文件，我想知道是否有办法检测文件中找到匹配项的哪一行。

I would like to search a .java file using Regular Expressions and I wonder if there is a way to detect one what lines in the file the matches are found.

例如，如果我用Java正则表达式查找匹配 hello ，有些方法会告诉我匹配是在第9,15和30行找到的？

For example if I look for the match hello with Java regular expressions, will some method tell me that the matches were found on lines 9, 15, and 30?

推荐答案

可能......正则表达真的恶魔！

免责声明：这并不是一个实用的解决方案，而是一个使用极好的正则表达式黑客扩展的方法的说明。此外，它仅适用于允许捕获组引用自身的正则表达式引擎。例如，您可以在Notepad ++中使用它，因为它使用PCRE引擎 - 但不是Java。

Disclaimer: This is not meant to be a practical solution, but an illustration of a way to use an extension of a terrific regex hack. Moreover, it only works on regex engines that allow capture groups to refer to themselves. For instance, you could use it in Notepad++, as it uses the PCRE engine—but not in Java.

假设您的文件是：

some code
more code
hey, hello!
more code

在文件底部，粘贴： 1：2：3：4：5：6：7 ，其中：是在其余代码中找不到的分隔符，其中这些数字至少与行数一样高。

At the bottom of the file, paste :1:2:3:4:5:6:7, where : is a delimiter not found in the rest of the code, and where the numbers go at least as high as the number of lines.

然后，获取第一个 hello的行，你可以使用：

Then, to get the line of the first hello, you can use:

(?m)(?:(?:^(?:(?!hello).)*(?:\r?\n))(?=[^:]+((?(1)\1):\d+)))*.*hello(?=[^:]+((?(1)\1)+:(\d+)))

第2组将捕获包含hello的第一行的行号。

The line number of the first line containing hello will be captured by Group 2.

• 在演示，请参阅右侧窗格中的第2组捕获。


• 黑客依赖于指向自身的组。在经典的@Qtax技巧中，这是通过（？> \ 1？）完成的。对于多样性，我使用了条件。

• In the demo, see Group 2 capture in the right pane.
• The hack relies on a group referring to itself. In the classic @Qtax trick, this is done with (?>\1?). For diversity, I used a conditional instead.

解释

• 正则表达式的第一部分是一个行程序员，它捕获了底部的行计数器越来越多的第1组


• 正则表达式的第二部分匹配 hello 并将行号捕获到第2组


• 在行序列中，（？：^（？:(？！hello）。）*（?: \r？\ n））匹配不包含hello的行。


• 仍在队长中，（？= [^：] +（（？（1）\ 1）：\ d +）） lookahead将我们带到第一个：，其中 [^：] + 然后是<的外括号code>（（？（1）\ 1）：\ d +））捕获到组1 ...如果组1设置为（？（1 ）\ 1）然后是组1，然后，无论是冒号还是一些数字。这可以确保每次线段管理员匹配一条线时，第1组扩展到的较长部分：1：2：3：4：5：6：7


• * 将线路船长归零次或多次


• 。*你好将该行与匹配


• 前瞻（？= [^ ：] +（（？（1）\ 1）+ :( \ d +）））与行队长中的相同，只是这次数字被捕获到第2组：（\d +）

-

• The first part of the regex is a line skipper, which captures an increasing amount of the the line counter at the bottom to Group 1
• The second part of the regex matches hello and captures the line number to Group 2
• Inside the line skipper, (?:^(?:(?!hello).)*(?:\r?\n)) matches a line that doesn't contain hello.
• Still inside the line skipper, the (?=[^:]+((?(1)\1):\d+)) lookahead gets us to the first : with [^:]+ then the outer parentheses in ((?(1)\1):\d+)) capture to Group 1... if Group 1 is set (?(1)\1) then Group 1, then, regardless, a colon and some digits. This ensures that each time the line skipper matches a line, Group 1 expands to a longer portion of :1:2:3:4:5:6:7
• The * mataches the line skipper zero or more times
• .*hello matches the line with hello
• The lookahead (?=[^:]+((?(1)\1)+:(\d+))) is identical to the one in the line skipper, except that this time the digits are captured to Group 2: (\d+)
-

参考

• Qtax技巧（最近由@AmalMurali授予额外奖励）


• 将一个单词替换为找到它的行数

• Qtax trick (recently awarded an additional bounty by @AmalMurali)
• Replace a word with the number of the line on which it is found

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