PHP preg_match


PHP preg_match() is a perl style regular expression function. It finds the specific pattern matches inside a string using regular expression. The regular expression pattern must be put inside / /. preg_match() function is much slower than other string functions such as str_replace() which do not support regular expressions.

<?PHP
$str="2000-08-12T03:54:54Z";
if (preg_match("/\d/",$str))
{
   echo "String contains number.";
}
?>

The matches can be stored into an array which is the 3rd parameter of the function.
<?PHP
$str="2000-08-12T03:54:54Z";
if (preg_match("/^((\d+)\-\d+\-\d+)T/",$str,$mats))
{
   echo "$mats[0]";   //2000-08-12T
   echo "$mats[1]";   //2000-08-12
   echo "$mats[2]";   //2000
}
?>

preg_match() function can match different patterns using | symbol.
<?PHP
$str="2000-08-12T03:54:54Z";
if (preg_match("/00|03/",$str))
{
   echo "String contains \"03\" or \"00\"";
}
?>


preg_match() is case sensitive. Similiar functions include ereg_replace(), ereg_match(), preg_replace(), str_replace().