What are the differences between perl and java regex capabilities?

java regex perl regex-lookarounds
Bohemian picture Bohemian · Dec 25, 2012 · Viewed 8.3k times · Source

What are the differences between perl and java with regard to what regular expression terms are supported?

This question is isolated to just the regular expressions, and specifically excludes differences in how regex can be used - ie the functions/methods available that use regex - and syntactic differences between the languages such as the java requirement to escape backslashes etc.

Of particular interest is the partial/occasional support java has for variable length look-behinds.

Answer

Rohit Jain picture Rohit Jain · Dec 25, 2012

The "Comparison to Perl 5" section of java.util.regex.Pattern lists many differences. For example, Java does not support conditional regex. For that, you need to use some external library like JRegex.

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