Reference - What does this regex mean?
This is a collection of common Q&A. This is also a Community Wiki, so everyone is invited to participate in maintaining it.
regex is suffering from give me ze code type of questions and poor answers with no explanation. This reference is meant to provide links to quality Q&A.
This reference is meant for the following languages: php, perl, javascript, python, ruby, java, .net.
This might be too broad, but these languages share the same syntax. For specific features there's the tag of the language behind it, example:
This question's answers are a collaborative effort: if you see something that can be improved, just edit the answer to improve it! No additional answers can be added here
Online tutorials
Quantifiers
Character Classes
Escape Sequences
Anchors
(Also see "Flavor-Specific Information → Java → The functions in Matcher")
Groups
Lookarounds
Modifiers
Other:
Common Tasks
Advanced Regex-Fu
Flavor-Specific Information
(Except for those marked with *, this section contains non-Stack Overflow links.)
General information
(Links marked with * are non-Stack Overflow links.)
Examples of regex that can cause regex engine to fail
Tools: Testers and Explainers
(This section contains non-Stack Overflow links.)
Online (* includes replacement tester, + includes split tester):
Offline:
