strcspn

Find length of initial segment not matching mask

Syntax

strcspn ( string $subject , string $mask [, int $start [, int $length ]] ) : int

Parameters

subject

The string to examine.

mask

The string containing every disallowed character.

start

The position in subject to start searching. If start is given and is non-negative, then strcspn() will begin examining subject at the start'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 start is given and is negative, then strcspn() will begin examining subject at the start'th position from the end of subject.

length

The length of the segment from subject to examine. If length is given and is non-negative, then subject will be examined for length characters after the starting position. If length is given and is negative, then subject will be examined from the starting position up to length characters from the end of subject.

Return

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

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

Examples

1 · subject mask

<?

$subject = "12345abcde12345abcde";
$mask = "abcde";

$return = strcspn($subject, $mask);

echo $return;

?>
5

2 · start · Negative

<?

$subject = "12345abcde12345abcde";
$mask = "abcde";
$start = -10;

$return = strcspn($subject, $mask, $start);

echo $return;

?>
5

3 · start · Non-negative

<?

$subject = "12345abcde12345abcde";
$mask = "abcde";
$start = 10;

$return = strcspn($subject, $mask, $start);

echo $return;

?>
5

4 · length · Negative

<?

$subject = "12345abcde12345abcde";
$mask = "abcde";
$start = -10;
$length = -5;

$return = strcspn($subject, $mask, $start, $length);

echo $return;

?>
5

5 · length · Non-negative

<?

$subject = "12345abcde12345abcde";
$mask = "abcde";
$start = 10;
$length = 5;

$return = strcspn($subject, $mask, $start, $length);

echo $return;

?>
5
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