On my local system i have the same results.
But if i use the Loops out of a function the foreach needs much more time.

function foreachLoop($array) {
// Foreach
$time_start = microtime(true);
foreach($array as $a) {
$devnull = $a;
}
$time_end = microtime(true);
return $time_end-$time_start;
}

This are my result:
0.142 seconds - foreach()
0.407 seconds - foreach() in function
0.159 seconds - while()
0.157 seconds - while() in function
0.150 seconds - for()
0.153 seconds - for() in function

I think speed depends on usage. Inline is the foreach faster. But in functions it is much slower.

Benji

$length = count($arr);
for($x = 0; $x < $length; $x++)
{
echo $arr[$x] . "";
}

is about four times faster than this

for($x = 0, $length = count($arr); $x < $length; $x++)
{
echo $arr[$x] . "";
}

Result:
while does not use any new ram, but the foreach loop will assign one new variable with "foreach($array => $entry) {..." when $entry is a new variable.
That is happening because the $entry variable wil stay after the loop is finished and has the last assigned value from array. But that should not result in noticeable ram increase, because $entry should be just a internal reference, as long as you have not modified it.

Hope that helps.

any thoughts?

This should be a better representation of a real world scenario. More often than not an array element will contain a string or another array so by hashing the numbers each element becomes 32 chars long.

When I run this modified benchmark the while loop comes out on top, and the foreach loop is the slowest.

Over the years it turned out that its ALWAYS good to read the whole documentation, even about the basic things - because theres always a posibility youll find something you didnt know before.

Example? For me, things like passing the whole arrays instead of singular variable to the particular built-in function, like strtr() - http://pl.php.net/strtr

Now Im using this with arrays in my own function that creates friendly URLs.

Sorry for offtop :).

All what we mentioned is available in the PHP docu:
http://de3.php.net/manual/en/control-structures.for.php
Maybe we should a little bit more to save some time :D

The situation I jumped on this idea was quite odd. I have read some fiery discussion on the web, the topic was something like:

- faster script vs. less coding

There was rather big flame about the loops, whether its better to call the count() within the loop on every iteration or to call it just once before the loop, but with the cost of more lines of code.

I thought: wait a minute, after we call for() we define $i, but its done just this once, then the loop doesnt go back to it - so why dont we define one more variable there?

Then I gave it a shoot and tested in different situations - it worked wery well so I just started to use it and tell people about it (if they didnt know this yet).

Cheers!