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

strspn --  Find length of initial segment matching mask


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:

= 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 4.0B1 this function is binary safe. Additionally it accepts two optional integer parameters that can be used to define the starting position and the length of the string to examine.

echo strspn("foo", "o", 1, 2); // 2

See also strcspn().