PHP Manual: strspn

strspn

(PHP 3 >= 3.0.3, PHP 4, PHP 5)

strspn -- Find length of initial segment matching mask

Description

int strspn ( string str1, string str2 [, int start [, int length]] )

Returns the length of the initial segment of str1 which consists entirely of characters in str2.

The line of code:

<?php
$var = strspn("42 is the answer, what is the question ...", "1234567890");
?>

will assign 2 to $var, because the string "42" will be the longest segment containing characters from "1234567890".

As of PHP 4.3.0, strspn() accepts two optional integer parameters that can be used to define the start position and the length of the string to examine.

<?php
echo strspn("foo", "o", 1, 2); // 2
?>

Note: This function is binary-safe.