| Re: strpos() before str_replace()? Or, maybe strtr()? [message #184920 is a reply to message #184918] |
Sun, 16 February 2014 13:55   |
J.O. Aho
Messages: 194
Registered: September 2010
Karma:
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Senior Member |
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On 16/02/14 10:49, Jason C wrote:
> I know that I'm talking about microseconds here, so this is really just for the sake of furthering my own education.
>
> I'm looping through roughly 100,000 values:
>
> $userArr = array(
> "something" => "anything",
> ...
> );
>
> foreach ($userArr as $key => $val) {
> $firstname = str_replace($key, "****", $firstname);
> $lastname = str_replace($key, "****", $lastname);
> }
>
> Both $firstname AND $lastname could contain any of the keys, but could only potentially contain one key each. It's likely, though, that neither will contain any of the keys.
>
> Would it be faster to use strpos() before each str_replace(), like so?:
Yes, if you only make str_replace() when it really need it, then the
code will be faster and require less CPU cycles (of course the faster
the machine, the less of the ill effects you will notice, but it will
still be there).
> foreach ($userArr as $key => $val) {
> if (strpos($firstname, $key) !== false)
> $firstname = str_replace($key, "****", $firstname);
>
> if (strpos($lastname, $key) !== false)
> $lastname = str_replace($key, "****", $lastname);
> }
>
> My instinct is that it would be the same, if not marginally slower; allowing a potential computation time for 100,002 strpos() as opposed to 100,000 str_replace().
>
> Or, would strtr() be faster? I've never actually used this function in practice; I think it's a slow function, but have never tested it, and don't remember where I read that:
>
> $firstname = strtr($firstname, $userArr);
> $lastname = strtr($lastname, $userArr);
>
> Any other suggestions on what might be the fastest option?
Would value the CPU and time usage to be around the same as for
str_replace(), they both need to find the string and then build the new one.
--
//Aho
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