STRSPN(3) 1 STRSPN(3)
strspn - Finds the length of the initial segment of a string consisting entirely of characters contained within a given mask.
SYNOPSIS
int strspn (string $subject, string $mask, [int $start], [int $length])
DESCRIPTION
Finds the length of the initial segment of $subject that contains only characters from $mask.
If $start and $length are omitted, then all of $subject will be examined. If they are included, then the effect will be the same as call-
ing strspn(substr($subject, $start, $length), $mask) (see "substr" for more information).
The line of code:
<?php
$var = strspn("42 is the answer to the 128th question.", "1234567890");
?>
2 to $var, because the string "42" is the initial segment of $subject that consists only of characters contained within "1234567890".
PARAMETERS
o $subject
- The string to examine.
o $mask
- The list of allowable characters.
o $start
- The position in $subject to start searching. If $start is given and is non-negative, then strspn(3) will begin examining $sub-
ject at the $start'th position. For instance, in the string ' abcdef', the character at position 0 is ' a', the character at posi-
tion 2 is ' c', and so forth. If $start is given and is negative, then strspn(3) will begin examining $subject at the $start'th
position from the end of $subject.
o $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 VALUES
Returns the length of the initial segment of $subject which consists entirely of characters in $mask.
EXAMPLES
Example #1
strspn(3) example
<?php
// 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));
?>
The above example will output:
int(0)
int(2)
int(1)
NOTES
Note
This function is binary-safe.
SEE ALSO
strcspn(3).
PHP Documentation Group STRSPN(3)