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Are Python and JavaScript regular expression syntax identical?

If not, then:

  1. What are the important differences between them
  2. Is there a python library that "implements" JavaScript regexps?
Chad Birch
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Dave Peck
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3 Answers3

31

There is a comparison table here:

Regex Flavor Comparison

Bernhard Barker
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EBGreen
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  • Thanks! My attempts at googling the answer failed. Now, I guess the follow up question is: "Is there a python library that 'implements' javascript regexps?" – Dave Peck Mar 11 '09 at 21:59
  • I don't know of one. What is the root reason for wanting one? – EBGreen Mar 12 '09 at 13:14
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    I'd like a Python library compatible with EMCA regex because I want consistency between a regex search in Python on the back-end and a Javascript one on the front-end. – Brian M. Hunt Jul 06 '10 at 14:05
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    The link point to TOC now. Wikipedia has some resources on the subject: https://en.wikipedia.org/wiki/Comparison_of_regular_expression_engines – Vajk Hermecz May 30 '16 at 16:03
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    The link isn't useful anymore. It would have been better to answer the question directly. – Akh Sep 06 '16 at 00:05
7

Part 1
They are different; One difference is Python supports Unicode and Javascript doesn't.

Part 2
Read Mastering Regular Expressions. It gives information on how to identify the back-end engines (DFA vs NFA vs Hybrid) that a regex flavour uses. It gives tons of information on the different regex flavours out there.

There is way too much information to convey on a single SO answer, so you're better off having a solid piece of reference material on the subject.

Gavin Miller
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2

http://www.regular-expressions.info/javascript.html vs http://www.regular-expressions.info/python.html

Alex Reitbort
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