   #PHP Manual Function Reference qdom_tree ereg_replace

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XCII. Regular Expression Functions (POSIX Extended)

Introduction

     Tip: 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
     expression syntax.

   Warning

   These regular expression functions are not binary-safe. The PCRE
   functions are.

   Regular expressions are used for complex string manipulation in PHP.
   The functions that support regular expressions are:

     * ereg()
     * ereg_replace()
     * eregi()
     * eregi_replace()
     * split()
     * spliti()

   These functions all take a regular expression string as their first
   argument. 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.

Requirements

   No external libraries are needed to build this extension.

Installation

   Warning

   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.

Runtime Configuration

   This extension has no configuration directives defined in php.ini.

Resource Types

   This extension has no resource types defined.

Predefined Constants

   This extension has no constants defined.

Examples

   Example 1. Regular Expression Examples
   <?php
   // Returns true if "abc" is found anywhere in $string.
   ereg("abc", $string);
   // Returns true if "abc" is found at the beginning of $string.
   ereg("^abc", $string);
   // Returns true if "abc" is found at the end of $string.
   ereg("abc$", $string);
   // Returns true if client browser is Netscape 2, 3 or MSIE 3.
   eregi("(ozilla.[23]|MSIE.3)", $HTTP_USER_AGENT);
   // Places three space separated words into $regs[1], $regs[2] and
   $regs[3].
   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);
   ?>

See Also

   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
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