strspn()

strspn() — Finds the length of the initial segment of a string consisting entirely of characters contained within a given mask.

Built-in function of PHP 8.5. The manual lists it as available in PHP 4, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

Signature

strspn(string $string, string $characters, int $offset = 0, ?int $length = null): int

Parameters

Parameter	Type	What it takes
$string	string	The string to examine.
$characters	string	The list of allowable characters.
$offset	int	The position in string to start searching.
$length	?int	The length of the segment from string to examine.

Return value

Returns the length of the initial segment of string which consists entirely of characters in characters. Note: When a offset parameter is set, the returned length is counted starting from this position, not from the beginning of string. When a offset parameter is set, the returned length is counted starting from this position, not from the beginning of string.

Example

A runnable snippet:

// subject does not start with any characters from mask var_dump(strspn("foo", "o")); // examine two characters from subject starting at offset 1 var_dump(strspn("foo", "o", 1, 2)); // examine one character from subject starting at offset 1 var_dump(strspn("foo", "o", 1, 1));

Output:

int(0) int(2) int(1)

Changelog

Version	Change
8.0.0	length is nullable now.