[RESOLVED] in_array() or isset()...which faster?

[sneakyimp]

i'm setting up a page with some 60 checkboxes on it. if the checkbox is set, the POST value for 'subcat', which is an array, will have one additional member in it.

something like:

<?
    foreach($current_cat['subcats'] as $key=>$subcat) {
?>
<input type="checkbox" name="subcats[<?=$subcat['id'] ?>]" value="<?=$subcat['id'] ?>">
<?
    } // each subcat
?>

if a user submits the form and there is some error, i want to make sure all the checkboxes previously selected are still selected (because there are TONS of them). So i'm going to need to add some logic to add 'checked' to a form input tag if the form was previously checked.

QUESTION: would this be faster:

if (in_array($subcat['id'], $_POST['subcats'])) echo ' checked';

or this:

if (isset($_POST['subcats'])) echo ' checked';

[Weedpacket]

I haven't done any experimentation, but my reckoning would be that isset() would be a bit faster; otherwise you need to make a series of actual value comparisons (on the order of n*n/2 comparisons, where n is the number of checkboxes).

[MarkR]

If you mean runtime performance, the answer is: You don't care.

Use whichever makes more sense in the context you use it in.

The difference will be so tiny that you really don't care- honestly.

If you're running it in a massively CPU intensive task that does this inside a loop going round 10,000,000 times or more, get a profiler. Otherwise, you don't care.

Mark

[sneakyimp]

thanks!