Expression régulière

Voir cette page sur les RegEx

The following description is an overview of available signs which can be used in regular expressions. This chapter is supposed to be a references for the different regex elements.

Common matching symbols

Regular Expression Description
Matches any character
regex must match at the beginning of the line
Finds regex must match at the end of the line
Set definition, can match the letter a or b or c
Set definition, can match a or b or c followed by either v or z
When a "^" appears as the first character inside [] when it negates the pattern. This can match any character except a or b or c
Ranges, letter between a and d and figures from 1 to 7, will not match d1
Finds X or Z
Finds X directly followed by Z
Checks if a line end follows


The following metacharacters have a pre-defined meaning and make certain common pattern easier to use, e.g. \d instead of [0..9].

Regular Expression Description
Any digit, short for [0-9]
A non-digit, short for [^0-9]
A whitespace character, short for [ \t\n\x0b\r\f]
A non-whitespace character, for short for [^\s]
A word character, short for [a-zA-Z_0-9]
A non-word character [^\w]
Several non-whitespace characters
Matches a word boundary. A word character is [a-zA-Z0-9_] and \b matches its bounderies.


A quantifier defines how often an element can occur. The symbols ?, *, + and {} define the quantity of the regular expressions

Regular Expression Description
Occurs zero or more times, is short for {0,}
Occurs one or more times, is short for {1,}
Occurs no or one times, ? is short for {0,1}
Occurs X number of times, {} describes the order of the preceding liberal
Occurs between X and Y times
? after a qualifier makes it a "reluctant quantifier", it tries to find the smallest match.