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. */
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