how do I check a string for white space in php? 3

[farley99]

how do I check for a string for white space in php?

$str="hello";
$str2="hello man";

if(hasWhiteSpace($str))
echo "str be whitey";

if(hasWhiteSpace($str2))
echo "str2 be whitey";

is there a function for hasWhiteSpace?

 

[sleipnir214]

preg_match('/\s/', $somestring)

will return a 1 when at least one whitespace character has been found in $somestring and a zero if not.


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[m98marba]

I would recommend the use of strpos() (see example at

http://se2.php.net/manual/en/function.strpos.php)

because strpos() does not involve the overhead that preg_match() do.

You should try to avoid the use of regular expression functions if you don't need fancy rules.

 

[sleipnir214]

Keep in mind, however, that if you use strpos(), you have to invoke the function multiple times, once for each character that constitutes whitespace: space, tab, newline, return, formfeed.

preg_match() will match all of those in one go.

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[DRJ478]

m98marba
What kind of overhead do you refer to? I see no mention of overhead in the PHP documentation. The only thing I see refered to in connection with strpos() is strstr() which is more memory intensive.
Please share your knowledge.
Thanks.

 

[m98marba]

DRJ478
I havn't done any benchmarking to compare strpos() and preg_match() myself. And I don't know exactly how the (quite sofisticated) matching machinery is coded.

But, simply speaking, because preg_match() is made to handle such a variety of patterns (see

http://se.php.net/manual/en/ref.pcre.php)

you may realize that it will in most cases take more CPU-power compared to, i.e., a function like strpos(). The only thing strpos($haystack, $needle) do is finding the first occurance of $needle in $haystack so it is actually designed for that particular task so it should be faster. Moreover, I think it's mentioned somewhere in the manual (not sure can't find it) and that what I learnd myself from other programmers.

With overhead I just meant "machinery" to handle the regular expression patterns. Sorry if I was a bit unclear.

/Markus