In a regular expression, the question mark makes the preceding token optional.| www.regular-expressions.info
Explanation of the regular expression flavor used by the XQuery and XPath functions fn:matches, fn:replace and fn:tokenize.| www.regular-expressions.info
How to Find or Validate an Email Address| www.regular-expressions.info
In a regular expression, the asterisk or star causes the preceding token to be matched zero or more times, and the plus one or more times.| www.regular-expressions.info
The utility from the UNIX world, but now available on all platforms, including Windows, that first made regular expressions popular| www.regular-expressions.info
Understanding how a regex engine works internally enables you to craft better regular expressions by learning how to think like a regex engine.| www.regular-expressions.info
Learn how to use PHP’s three sets of regular expression functions| www.regular-expressions.info
In a regular expression, parentheses can be used to group regex tokens together and for creating backreferences. Backreferences allow you to reuse part of the regex match in the regex, or in the replacement text.| www.regular-expressions.info
Learn how to use regular expressions with Tcl’s regexp and regsub commands| www.regular-expressions.info
Explains the two regex flavors defined in the POSIX standard: Basic Regular Expressions and Extended Regular Expressions| www.regular-expressions.info