Best performance: count in a loop or outside?

Question

Perhaps this question has been asked several times but I can't find a proper answer here or in Google so apologies if this is a dupe or something like that but here I go...

What's the best way to achieve performance in a loop:

count($var) each time

for ($i=0;$i<count($var);$i++) {
    // do something
}

put a var outside and use that var:

$cnt = count($var);
for ($i=0;$i<$var;$i++) {
    // do something
}

Is there any PHP script or code to show execution times and so on? I mean something for benchmark and see the results on this cases?

@j08691 that's because I don't know how to benchmark it properly for see execution times and memory and so on and that's why I asked about this and thanks for the downvote (to the person who did) ;) — ReynierPM, Feb 24 '16 at 15:04
see here: http://www.phpbench.com/ - use `count()` outside the `for` — Sebastian Brosch, Feb 24 '16 at 15:05

score 1 · Answer 1 · answered Feb 24 '16 at 15:06

1

I'm pretty sure you meant

for ($i=0;$i<$cnt;$i++) {

in the second snippet

yes... it's more efficient to only do the count once.

it can also be done like so

for ($i=0, $cnt=count($var); $i<$cnt; $i++) {

answered Feb 24 '16 at 15:06

Brad Kent

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Best performance: count in a loop or outside?

1 Answers1