Speed differences within PHP

[newttster]

I am not sure how to test this. Which would be faster?

This one.

$t=$db->query("SELECT agility FROM userstats WHERE userid={['$ir['userid']}");
$r=$db->fetch_row($t);

 

Or this one.

$t=($db->fetch_row($db->query("SELECT agility FROM userstats WHERE userid={$ir['userid']}")));

 

It seems to me that the second one would be faster but I'm not sure.

Or is it just a case of keeping the code shorter?

[Spudinski]

I am not sure how to test this. Which would be faster?

This one.

$t=$db->query("SELECT agility FROM userstats WHERE userid={['$ir['userid']}");
$r=$db->fetch_row($t);

 

Or this one.

$t=($db->fetch_row($db->query("SELECT agility FROM userstats WHERE userid={$ir['userid']}")));

 

It seems to me that the second one would be faster but I'm not sure.

Or is it just a case of keeping the code shorter?

Theoretically, the second one would be faster, but that's just theory.

Any number of things can make it differ.

The reason I can think of is that the second variable is never assigned, thus using less memory.

But, in terms of how PHP executes those statements, it should be exactly the same.

The bottle-neck there is that ->query() isn't a form of a closure - if it were, it would be faster(such as PDO).

[newttster]

The bottle-neck there is that ->query() isn't a form of a closure - if it were, it would be faster(such as PDO).

Can you explain that further, please. I don't quite understand what you mean by closure.

[Spudinski]

Can you explain that further, please. I don't quite understand what you mean by closure.

I'm not even going to try explaining closures, it could take an eternity to understand.

Instead, here's a wiki with a lot of different people taking their own approaches at explaining it.

http://stackoverflow.com/questions/111102/how-do-javascript-closures-work

I tried to write a proper example in PHP, but unfortunately I couldn't create a good example, so see the following link for practical applications of closured in PHP: http://www.vancelucas.com/blog/practical-uses-for-php-5-3-closures/

In PHP, a closure makes use of the same semantics as an anonymous functions, but I'm not even going to stand by this point at all.

In JavaScript, I use closures daily - there are many examples: the whole of jQuery is riddled with closures everywhere.

But, they are fairly easy and convenient - if you know your variable scope, and how data flows trough an application.

Edit: This is also a good read: https://wiki.php.net/rfc/closures

Edited August 10, 2012 by Spudinski

[Someone]

Note that } elseif() { is somewhat faster than } else if() {

===================================

Test (100,000,000 runs):

<?php
$start = microtime(true);
for($i = 0; $i < 100000000; $i++) {
   if(2 === 0) {} else if(2 === 1) {} else {}
}
$end = microtime(true);
echo "1: ".($end - $start)."\n";
unset($start, $end);

$start = microtime(true);
for($i = 0; $i < 100000000; $i++) {
   if(2 === 0) {} elseif(2 === 1) {} else {}
}
$end = microtime(true);
echo "2: ".($end - $start);
?>

===================================

Result (depending on hardware configuration):

1: 20.026723146439

2: 20.20437502861

:):):):):):):):):):):):):):):)

 

 

I LOL'ed