Regular expressions are used for complex string manipulation in PHP. The functions that support regular expressions are:
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.
Example 1. Regular expression examples ereg("abc",$string); /* 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 $string. */ eregi("(ozilla.[23]|MSIE.3)",$HTTP_USER_AGENT); /* Returns true if client browser is Netscape 2, 3 or MSIE 3. */ ereg("([[:alnum:]]+) ([[:alnum:]]+) ([[:alnum:]]+)", $string,$regs); /* Places three space separated words into $regs[1], $regs[2] and $regs[3]. */ $string = ereg_replace("^","<BR>",$string); /* Put a <BR> tag at the beginning of $string. */ $string = ereg_replace("$","<BR>",$string); /* Put a <BR> tag at the end of $string. */ $string = ereg_replace("\n","",$string); /* Get rid of any carriage return characters in $string. */ |