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 calling 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
$var
subject
The string to examine.
The list of allowable characters.
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
.
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
.
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 ofsubject
.
<?php $var = strspn("42 is the answer to the 128th question.", "1234567890"); ?>
<?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)
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