for() evaluation

[Pig]

I am setting up a potentially massive for() loop, and I want to make sure it is as streamlined as possible by removing everything unecessary from the loop. Right now, the loop looks like:

for( $i = strtotime($_POST['start']); $i < strtotime($_POST['end']); $i = $i +1800)
{ 
     //do stuff here
}

Here is my question. Is the strtotime($_POST['end']) function called once, or for every iterration of looped. I know the expression is evaluated every iteration, but does that mean strtotime is as well? Basically, does PHP actually read through the second and third arguements, or is that just an abstraction created by the coders to make it easier for us.

I can easily just define the strtotime results as vars before the loop, but I would like to know how this function actually works.

[bad76]

Hi,
try this:

$j=100;
for($i=0; $i<$j; $i++)
{
  echo $i;
  $j=-10;
}

I think this will echo just 0.
Then at every cycle php look at $j value.

Even if we put strtotime(...) instead of $j.

(I don't try it... but i'm enough sure...)

see you

[Pig]

I don't understand how this is an answer to my question.

[bad76]

Yes,
strtotime($POST['end']); is always evaluated, at EVERY iteration, because if you change $POST['end'] value you can make the for's execution shorter or infinite.

[Pig]

OK, I think I got you now.

[bad76]

Eh,
I know, it's not easy understand me, some times. 😃

bye bye