strrpos
The second parameter is a set of allowed characters.
strspn will return an zero-based index of a first non-allowed character.
strspn
(PHP 4, PHP 5)
strspn — Vindt de lengte van een initieel segment invoermasker
Beschrijving
int strspn
( string $str1
, string $str2
)
Geeft de lengte van het initieel segment van str1 die uitsluitend bestaat uit karakters in str2 .
$var = strspn ("42 is het antwoord, wat is de vraag ...", "1234567890");
zal 2 in $var stoppen, omdat de string "42" het langste segment bestaande uit de tekens "1234567890" is.
Zie ook strcspn().
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User Contributed Notesstrspn
Dmitry Mazur
04-Mar-2009 06:23
04-Mar-2009 06:23
barry dot balkowski at gmail dot com
08-Aug-2008 09:12
08-Aug-2008 09:12
It took me some time to understand the way this function works…
I’ve compiled my own explanation with my own words that is more understandable for me personally than the official one or those that can be found in different tutorials on the web.
Perhaps, it will save someone several minutes…
<?php
strspn(string $haystack, string $char_list [, int $start [, int $length]])
?>
The way it works:
- searches for a segment of $haystack that consists entirely from supplied through the second argument chars
- $haystack must start from one of the chars supplied through $char_list, otherwise the function will find nothing
- as soon as the function encounters a char that was not mentioned in $chars it understands that the segment is over and stops (it doesn’t search for the second, third and so on segments)
- finally, it measures the segment’s length and return it (i.e. length)
In other words it finds a span (only the first one) in the string that consists entirely form chars supplied in $chars_list and returns its length
B Crawford
03-Oct-2007 12:20
03-Oct-2007 12:20
This function is significantly faster for checking illegal characters than the equivalent preg_match() method.