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Line 23: − * '\s' - any whitespace character+ − * '\b' - a word boundary − * '\d' - a digit
trying to make this article less lame
A '''regular expression''' is used in computer software to define a sequence of characters.<ref>"A regular expression, or regex for short, is a pattern describing a certain amount of text." [http://www.regular-expressions.info/quickstart.html Regular Expression Quick Start] </ref>
A '''regular expression''' is used in computer software to define a sequence of characters.<ref>"A regular expression, or regex for short, is a pattern describing a certain amount of text." [http://www.regular-expressions.info/quickstart.html Regular Expression Quick Start] </ref>
In general, any character will match itself, but there are a dozen special characters, including the [[escape character]].
To match any of 2 or more characters, enclose them in square brackets. For example,
gr[ae]y
will match ''gray'' or ''grey''.
A regular expression is matched from left to right and is processed one [[token]] at a time. Certain characters have special meanings within the description of a regular language:
A regular expression is matched from left to right and is processed one [[token]] at a time. Certain characters have special meanings within the description of a regular language:
* '\\' - a literal backslash
* '\\' - a literal backslash
* '\.' - a literal period
* '\.' - a literal period
Regular expressions have also been extended by many languages, some of which extend them to the point where they are able to match a wider range of languages than is specified by a regular language.
Regular expressions have also been extended by many languages, some of which extend them to the point where they are able to match a wider range of languages than is specified by a regular language.