Urgent Array traversal

khalsaji99

Hey !

Can someone show me example of traversing an array which I do NOT know the size ?

Thanks in advance -

MrAlaska

First you get the size:

http://www.php.net/manual/en/function.count.php

For performance purposes, it is MUCH more efficient to calculate the size into a variable than it is to put the count inside of a loop statement.

For instance:

/ good /
$count= count($array);
for ($i=0;$i<$count;$i++){

Beats the HELL out of:

/ bad /
for ($i=0;$i<count($array);$i++){

khalsaji99

Okay, I got the size !

Then how do I traverse the array ?

MrAlaska

That is a pretty basic question to be assigning an URGENT tag to in the subject line, especially since I already wrote more than half the code. Your aren't trying to cheat on a test are you?

khalsaji99

No mate !

I`m still expecting some help...

MrAlaska

I'm keeping an eye on you...
$count= count($array);
for ($i=0;$i<$count;$i++){
echo "$array[$i] <br>";
}

khalsaji99

Thanks mate !

Appreciate your help !

Weedpacket

That will work for a non-associative array, but anything else will have trouble.

foreach($array as $val)
{ echo $val.'<br>';
}

or, if you ned the key:

foreach($array as $key=>$val)
{ echo "array[$key]=$val<br>";
}

If you're using PHP3:

reset($array);
while(list($key,$val)=each($array))
{ echo "array[$key]=$val<br>";
}

Five minutes with the manual can save you two hours on the forums.

MrAlaska

Originally posted by Weedpacket
That will work for a non-associative array, but anything else will have trouble.

Thanx, I totally spaced out foreach and while loops. The guy said it was 'urgent' and I got excited and just posted the first thing that came to mind. I hope everything turned out all right.

Weedpacket

I'm in no position to fault anyone at the moment - I've just realised I was recently posting while under the influence of a massive bogon flux myself.

count($array) is certainly a key function to be aware of in situations like this - it certainly can't hurt to know and can even prove useful in ways that just "traversing the array" won't provide.

I think I'll spend a bit of time playing with those array_* functions. They don't seem to be as fast as writing their equivalents by hand, but might make things easier to read...