XCVII. Regular Expression Functions (POSIX Extended)
PHP also supports regular expressions using a Perl-compatible syntax
using the PCRE functions. Those functions
support non-greedy matching, assertions, conditional subpatterns, and a
number of other features not supported by the POSIX-extended regular
These regular expression functions are not binary-safe. The PCRE functions are.
Regular expressions are used for complex string manipulation.
PHP uses the POSIX extended regular expressions as defined by POSIX
1003.2. For a full description of POSIX regular expressions see the regex
man pages included in the regex directory in the PHP distribution. It's
in manpage format, so you'll want to do something along the lines of
man /usr/local/src/regex/regex.7 in order to read it.
No external libraries are needed to build this extension.
Do not change the TYPE unless you know what you are doing.
To enable regexp support configure PHP
--with-regex[=TYPE]. TYPE can be one of
system, apache, php. The default is to use php.
The windows version of PHP has built in
support for this extension. You do not need to load any additional
extension in order to use these functions.
This extension has no configuration directives defined in php.ini.
This extension has no resource types defined.
This extension has no constants defined.
Example 1. Regular Expression Examples
// Returns true if "abc" is found anywhere in $string.
// Returns true if "abc" is found at the beginning of $string.
// Returns true if "abc" is found at the end of $string.
// Returns true if client browser is Netscape 2, 3 or MSIE 3.
// Places three space separated words into $regs, $regs and $regs.
ereg("([[:alnum:]]+) ([[:alnum:]]+) ([[:alnum:]]+)", $string, $regs);
// Put a <br /> tag at the beginning of $string.
$string = ereg_replace("^", "<br />", $string);
// Put a <br /> tag at the end of $string.
$string = ereg_replace("$", "<br />", $string);
// Get rid of any newline characters in $string.
$string = ereg_replace("\n", "", $string);
For regular expressions in Perl-compatible syntax have a look at the
PCRE functions. The simpler shell style
wildcard pattern matching is provided by fnmatch().
- Table of Contents
- ereg_replace -- Replace regular expression
- ereg -- Regular expression match
- eregi_replace -- replace regular expression case insensitive
- eregi -- case insensitive regular expression match
- split -- split string into array by regular expression
- spliti --
Split string into array by regular expression case insensitive
- sql_regcase --
Make regular expression for case insensitive match
Cheap domain registration
& cheap domain name transfer
Active-Domain.com : Domain register and domain
documentation is provided only for the benefits of our hosting customers.
For authoritative source of the documentation, please refer to http://www.php.net/docs.php