According to Wikipedia, a regular expression (abbreviated regex or regexp) is a sequence of characters that forms a search pattern, mainly for use in pattern matching with strings, or string matching, i.e. "find and replace"-like operations.

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How do you learn Regular Expressions? [closed]

I'm not asking where to learn. I've found lots of good resources online, and books etc. But how the heck do I tackle them. Where is the start of it, the end? When does the regexp processor advance on ...
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2answers
280 views

Documentation often ommits to specify which flavour of regular expression to use, so is there a default flavour that we should all be familiar with?

Often I come across documentation that says "use a regular expression here" I have to spend quite some time digging around trying to work out which regular expression format they are expecting. As ...
12
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7answers
768 views

What is more standard shortening for “regular expression”, “regex” or “regexp”? [closed]

I want to know what is more standard way to call regular expression in short way. I have seen both, regex and regexp. Google says regex has almost 2 as much hits that regexp, but it depends on way I ...
4
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2answers
998 views

Using lookahead assertions in regular expressions

I use regular expressions on a daily basis, as my daily work is 90% in Perl (legacy codebase, but that's a different issue). Despite this, I still find lookahead and lookbehind to be terribly ...
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10answers
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A better way of doing Regex? [duplicate]

I really dislike regular expressions, each time I come back to it I seem to have to relearn it. It's also incredibly hard to maintain, modify and at a glance understand what it is doing. Has anyone ...
12
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6answers
556 views

What can / should be done with regular expressions?

I've recently learnt regular expressions and I love writing / using them. I'm looking for ideas and more opportunities to use them, however I don't want to overuse them as an all purpose tool, as ...
3
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1answer
730 views

can a regex search engine for the web be done and if so, how?

I think it would be a great idea if we had a regular expression search engine, but can it be done? It seems impossible since there's no feasible way of indexing such a huge amount of data properly and ...
1
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2answers
348 views

Regexp or custom parsing algo?

I was trying to parse a java properties file to avoid some Properties loading pitfalls (non ordering, loss of comments). (Property are of the form 'key = value' where the value can span on multiple ...
36
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0answers
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What does the Jamie Zawinski's quotation about regular expressions mean? [duplicate]

In a message to comp.emacs.xemacs, Jamie Zawinski once said: Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems. I've always ...
82
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25answers
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How far should one take e-mail address validation?

I'm wondering how far people should take the validation of e-mail address. My field is primarily web-development, but this applies anywhere. I've seen a few approaches: simply checking if there is ...