sort an array by values of another array

[birwin]

I have an array of store numbers in order.

$store_counter[$x]

It holds the value of store numbers for a retail chain, in order. Not all store numbers are consecutive.

$store_counter[0]=1
$store_counter[1]=4
$store_counter[2]=5
$store_counter[3]=6
$store_counter[4]=9
$store_counter[5]=11

etc.

I have sales in another array:

$tot_store_sales_w[0]=259332.55
$tot_store_sales_w[4]=379789.74
$tot_store_sales_w[5]=579929.39
$tot_store_sales_w[6]=280547.38
$tot_store_sales_w[9]=493220.34
$tot_store_sales_w[11]=382709.29

I want to change $store_counter to list the stores in order of their volume.

e.g. in the above example I want $store_counter to read:

$store_counter[0]=5
$store_counter[1]=9
$store_counter[2]=11
$store_counter[3]=4
$store_counter[4]=6
$store_counter[5]=1

My experience with arrays is slim. I would appreciate some help or directions on how to do this.

Thank you.

Brian

[barand]

Here's one approach

$store[0]["no"]=1 ;
$store[1]["no"]=4; 
$store[2]["no"]=5; 
$store[3]["no"]=6; 
$store[4]["no"]=9; 
$store[5]["no"]=11;
$store[0]["sales_w"]=259332.55; 
$store[1]["sales_w"]=379789.74; 
$store[2]["sales_w"]=579929.39; 
$store[3]["sales_w"]=280547.38; 
$store[4]["sales_w"]=493220.34; 
$store[5]["sales_w"]=382709.29;

function cmp($a,$b) {
	if ( $a["sales_w"] == $b["sales_w"]) {
		return 0;
	} else {
		return ( $a["sales_w"] < $b["sales_w"])?1:-1;
	}
}

usort($store,"cmp");
foreach($store as $k=>$v) {echo $store[$k]["no"] . "<br>";}

gives

5
9
11
4
6
1