Which is faster, preg_match or if comparision

keenlearner

Does anyone knows the first block of code is faster or the second block ? if I want to make the case insensitive comparison. Thanks.

$str = 'ABC';
if(preg_match("/^abc$/i",$str))
    echo 'Matched';

$str = 'ABC';
if($str == 'abc' || $str == 'ABC')
    echo 'Matched';

Piranha

If you want to make it case insensitive you have to add a lot of alternatives to the second way. With 3 letters it could be lots of strings:

abc
Abc
aBc
abC
ABc
AbC
aBC
ABC

But you can easily handle that by using [man]strcasecmp[/man] or [man]strtolower[/man] to get the whole string to lowercase.

Which one is fastest? I have no idea, use [man]microtime[/man] and run a couple of thousand strings (both matches and no matches) and you will see. But I would not worry about the time, it might differ one or two milliseconds (probably less), takes longer to ask the question than it ever will save.

keenlearner

I am worry because my application require a lot of string comparisons. I was told in other forum saying that strpos() or stripos() will be faster in this specific example, do you believe so ?

Piranha

Read my previous answer, it is all there.

NogDog

stripos will only let you know if one string is contained within another string, but not if they are the same. Using either of Piranha's suggestions will determine equivalency or not:

if(strtolower($str) === 'abc')
{
   // OK
}
// . . . or . . .
if(strcasecmp($str, 'abc') === 0)
{
   // OK
}

I would suggest using whichever one makes more sense to you and will be easier for you to maintain, unless a few microseconds here or there are truly critical to you, in which case you should run some metered tests using mircrotime() to get some empirical data.