用于格式化文件的正则表达式 [英] Regular Expression for formatting a file

问题描述

我的文件包含以特定模式开头的每行的数据

 1000000179 | abcd ..... 
 1000000180 | wedwedw ... 
 1000000181 | wnewedwed ... 

有10个数字后跟管道。



如何查找/替换没有此模式的行..例如..下面的第二行无效

 1000000179 | abcd ..... 
％d20000180 | wedwedw ... 
 1000000181 | wnewedwed ... 

解决方案

您需要的是负向前瞻。

表达式为： ^（？！\d {10}）。{10} \ |。*


< blockquote> （使用MultiLine选项）。

请注意它的逻辑：第一个公式是前瞻，检查与十位数不匹配的子串图案。其余的是一般模式，允许管道位于第11位的好的和坏的字符串。

有关环视的更多详细信息，请参阅本文 [ ^ ]。

这里的挑战，如：莫汉暗示，正在寻找负面的比赛。找到一个以10位数字和一根烟斗开头的线条是直截了当的，但你怎么找到一条不行的呢？



Here''sa将要执行此操作的正则表达式：

 ^（[^ |] * [^ | \d] [^ |] * \ ||。{10} [ ^ |]）

它仅匹配这些输入行的最后4个：

 1000000179 | abcd。 .... | ABC | 
 1000000180 | wedwedw ... | 234 | 
 1000000179 | abcd ..... 
％d20000180 | wedwedw ... 
 3214a23642 | abcd 
 123456789 |无论
 1234567890_abcde 

打破正则表达式，它正在寻找一行开头的两个条件之一：

1）任何非第一个管道前的数字（ [^ |] * [^ | \d] [^ |] * \ | ）

2）任何非管道字符第11位（。{10} [^ |] ）

My file has data with each line starting with a specific pattern

1000000179|abcd.....
1000000180|wedwedw...
1000000181|wnewedwed...

there are 10 numerals followed by a pipe.

How to find/replace lines that DO NOT have this pattern.. Eg.. the second line below is invalid

1000000179|abcd.....
%d20000180|wedwedw...
1000000181|wnewedwed...

解决方案

What you need is called negative lookahead.
The expression will be this one: ^(?!\d{10}).{10}\|.*




(with MultiLine option).
Please note it''s logic: the first formula is a lookahead that checks for substrings that do not match the "ten digits" pattern. The rest is a general pattern that allows both good and bad strings with the pipe at the 11th position.
For more details about lookaround, read this article[^].

The challenge here, as Mohan implied, is finding the "negative" match. It''s straightforward to find a line that starts with 10 digits and a pipe, but how do you find one that doesn''t?

Here''s a regex that will do it:

^([^|]*[^|\d][^|]*\||.{10}[^|])

It matches only the last 4 of these input lines:

1000000179|abcd.....|abc|
1000000180|wedwedw...|234|
1000000179|abcd.....
%d20000180|wedwedw...
3214a23642|abcd
123456789|whatever
1234567890_abcde

Breaking down the regex, it''s looking for one of two conditions at the beginning of a line:
1) Any non-digit before the first pipe ( [^|]*[^|\d][^|]*\| )
2) Any non-pipe character in the 11th position ( .{10}[^|] )

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