什么是匹配不在行尾的字符串的正则表达式? [英] What is a regex to match a string NOT at the end of a line?

问题描述

正则表达式 /abc$/ 将匹配出现在行尾的 abc.我如何做相反的事情?

The regex /abc$/ will match an abc that does appear at the end of the line. How do I do the inverse?

我想匹配不在行尾的 abc.

I want to match abc that isn't at the end of a line.

此外，我将使用正则表达式来替换字符串，所以我只想捕获abc，而不是字符串后面的任何内容，所以/abc.+$/ 不起作用，因为它不仅会替换 abc，还会替换 abc 之后的任何内容.

Furthermore, I'm going to be using the regex to replace strings, so I want to capture only abc, not anything after the string, so /abc.+$/ doesn't work, because it would replace not only abc but anything after abc too.

正确的正则表达式是什么?

What is the correct regex to use?

推荐答案

/abc(?!$)/

(?!$) 是一个负前瞻.它将查找没有直接跟在 $(行尾)

(?!$) is a negative lookahead. It will look for any match of abc that is not directly followed by a $ (end of line)

经过测试

• abcddee(匹配)
• dddeeeabc(不匹配)
• adfassdfabcs(匹配)
• fabcddee(匹配)

• abcddee (match)
• dddeeeabc (no match)
• adfassdfabcs (match)
• fabcddee (match)

将其应用于您的案例:

ruby-1.9.2-p290 :007 > "aslkdjfabcalskdfjaabcaabc".gsub(/abc(?!$)/, 'xyz')
  => "aslkdjfxyzalskdfjaxyzaabc" 

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