PHP substr()

substr() cuts a string with specified offset and length.

<?PHP
	$str="The best time is no time at that time";
    echo substr($str,0,3);  //The
	echo substr($str,4,4);  //best
?>

If no length is specified, the function returns the substring from the offset till the end of string.

<?PHP
	$str="The best time is no time at that time";
    echo substr($str,3);  //best time is no time at that time
?>

substr() also supports negative numbers.

<?PHP
	$str="The best time is no time at that time";
    echo substr($str,-3);  //ime
    echo substr($str,4,-3);  //best time is no time at that t
?>

Function substr_count() counts the occurrence of a substring in an input string.

<?PHP
    $str = "<li><a href=\"http://www.endmemo.com/index.php\">EndMemo</a></li>"    
	echo substr_count($str, "li"); //result is 2
?>

preg_match_all() can get the number of all matches using regular expression.

<?PHP
	$str = "match Can Be Case Insensitive with i modifier";
    echo preg_match_all("/se/",$str); //2
?>