[Resolved] array question

[bigswifty]

Hi folks.
Im running a script that creates a session csv file populated with 4 variable elements per line...

var[1],var[2],var[3],var[4]
var[1],var[2],var[3],var[4]
and so-on...

the number of lines can be from 1 to whatever, but will always have 4 vars per line

now the question is how can i get the sum of all instances of var[3] (always a number)

i could get the total if all var[3]'s were passed into another array.
but I can't seem to find the way of passing the vars.

heres a chunk of the code that extracts all of the data from the csv array...

if ($action=="submit") {
$ordre_id = (substr(uniqid (""), 2, 7));

	$fp = fopen ("./sessions/".$sessionid.".dat", "r");
	$row = 1;
	while ($data = fgetcsv ($fp, 500)) {
		$new_data[$row] = "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n".$data[0]."    ".$data[1]."\n".$data[3]." x ".$data[2]."    =    ".number_format(($data[2] * $data[3]),2);
		$row++;
		if (! empty($no_prod) ) {
			$no_prod = $no_prod + $data[3];
		}

		$tot_pos = number_format($tot_pos + ($data[2] * $data[3]),2);
	}

I just cant figure how to get the secondary data I need.

its a shopping cart type script, and what I need is to get the number total of the values of $data[3] (qty for each line item in the order) so I can calculate shipping costs based on number of items (this is why I can't simply count rows).

any suggestions?

[bigswifty]

I found a solution.

I just used another fgetcsv() to include only the $data[3] var and then ran array_sum on that.

It was fairly easy once I found where I was and what the code was doing.

so now I have a working number with which to calculate shipping.