PHP Manual
String Functions
Find length of initial segment not matching mask

strcspn

(PHP 4, PHP 5, PHP 7, PHP 8)

strcspn — Find length of initial segment not matching mask

Description

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

Returns the length of the initial segment of string which does not contain any of the characters in characters.

If offset and length are omitted, then all of string will be examined. If they are included, then the effect will be the same as calling strcspn(substr($string, $offset, $length), $characters) (see substr for more information).

Parameters

string

The string to examine.

characters

The string containing every disallowed character.

offset

The position in string to start searching.

If offset is given and is non-negative, then strcspn() will begin examining string at the offset'th position. For instance, in the string 'abcdef', the character at position 0 is 'a', the character at position 2 is 'c', and so forth.

If offset is given and is negative, then strcspn() will begin examining string at the offset'th position from the end of string.

length

The length of the segment from string to examine.

If length is given and is non-negative, then string will be examined for length characters after the starting position.

If length is given and is negative, then string will be examined from the starting position up to length characters from the end of string.

Return Values

Returns the length of the initial segment of string which consists entirely of characters not in characters.

Note:
When a offset parameter is set, the returned length is counted starting from this position, not from the beginning of string.

Changelog

Version	Description
8.4.0	Prior to PHP 8.4.0, when `characters` was the empty string, the search would incorrectly stop at the first null byte in `string`.
8.0.0	`length` is nullable now.

Examples

Example #1 strcspn() example

<?php
$a = strcspn('banana', 'a');
$b = strcspn('banana', 'abcd');
$c = strcspn('banana', 'z');
$d = strcspn('abcdhelloabcd', 'a', -9);
$e = strcspn('abcdhelloabcd', 'a', -9, -5);

var_dump($a);
var_dump($b);
var_dump($c);
var_dump($d);
var_dump($e);
?>

The above example will output:

int(1)
int(0)
int(6)
int(5)
int(4)

Notes

Note: This function is binary-safe.