strspn
Finds the length of the initial segment of a string consisting
entirely of characters contained within a given mask.
Description
int strspn
( string $subject
, string $mask
[, int $start
[, int $length
]] )
If start and length
are omitted, then all of subject will be
examined. If they are included, then the effect will be the same as
calling strspn(substr($subject, $start, $length),
$mask) (see substr
for more information).
The line of code:
will assign
2 to
$var,
because the string "42" is the initial segment
of
subject that consists only of characters
contained within "1234567890".
Parameters
-
subject
-
The string to examine.
-
mask
-
The list of allowable characters.
-
start
-
The position in subject to
start searching.
If start is given and is non-negative,
then strspn 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 strspn 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 Values
Returns the length of the initial segment of subject
which consists entirely of characters 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
Example #1 strspn 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:
Notes
Note: This function is
binary-safe.