Regular expressions pcre2 cheatsheet
Regular expressions pcre2: Quantifiers, groups and alternation
8 common Regular expressions pcre2 tasks.
Repeat a pattern
Match between two and four letters a. Also: * zero or more, + one or more, ? optional.
a{2,4}
Match as little as possible
Add ? after a quantifier to make it lazy. This matches the shortest text between the quotes.
".*?"
Capture parts of a match
Capture the year, month and day of an ISO date as groups 1, 2 and 3.
(\d{4})-(\d{2})-(\d{2})
Group without capturing
Group for alternation or repetition without creating a numbered group.
(?:https?|ftp)://
Name a capture group
Capture a year by name. JavaScript, PCRE and Java use (?<name>...); Python uses (?P<name>...).
(?<year>\d{4})
Match repeated text
Match a repeated word such as the the, using a backreference to the first group.
\b(\w+)\s+\1\b