regex101: PCRE (Legacy) Match Workspace

Pro

lookaroundthe literal text lookaround (case sensitive)

Non-Capturing Group(?:(?!(?:match|lookaround)).)*

*repeats the group contents below any number of times:

Negative Lookahead(?!(?:match|lookaround))

Non-Capturing Group(?:match|lookaround)

1st Alternativematch

matchthe literal text match (case sensitive)

2nd Alternativelookaround

lookaroundthe literal text lookaround (case sensitive)

.any character (except for line terminators)

matchthe literal text match (case sensitive)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

25 tokens

Regular Expression

lookaround(?:(?!(?:match|lookaround)).)*match

New

Lookahead and lookbehind, collectively called "lookaround", are zero-length assertions just like the start and end of line, and start and end of word anchors explained earlier in this tutorial. The difference is that lookaround actually matches characters, but then gives up the match, returning only the result: match or no match. That is why they are called "assertions". They do not consume characters in the string, but only assert whether a match is possible or not. Lookaround allows you to create regular expressions that are impossible to create without them, or that would get very longwinded without them.