Want to reuse for loop but change condition from within loop

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Want to reuse for loop but change condition from within loop

garek007

Hi,

I have an object and need to set groups of values based on the condition. My loop looks like

for(s=0;s<product.system.length;s++){
xfa.resolveNode("form1.#pageSet.Page1.Subform1."+system+".Row["+s+"].Cell[0]").rawValue = product.system[0];
xfa.resolveNode("form1.#pageSet.Page1.Subform1."+system+".Row["+s+"].Cell[1]").rawValue = product.system[1];
xfa.resolveNode("form1.#pageSet.Page1.Subform1."+system+".Row["+s+"].Cell[3]").rawValue = product.system[2];
xfa.resolveNode("form1.#pageSet.Page1.Subform1."+system+".Row").instanceManager.addInstance(0);

}

So after I hit the end of product.system.length, I want to sub in another word for "system" and go through the loop again until I've hit the end of that group.

Product is an object and it has properties product.system, product.reagents, product.controls, and product.accessories.

I can do this if I make 4 separate for loops, but surely there is a cleaner way?

bionoid

Well, if you're looping through all the members of the product object, you could do this:

<script type="text/javascript">

var
	product = {
		system      : [1],
		reagents    : [1, 2],
		controls    : [1, 2, 3],
		accessories : [1, 2, 3, 4]
	},
	i, s;

for (i in product) {if (product.hasOwnProperty(i)) {
	for (s = 0; s < [COLOR="#FF0000"]product[i][/COLOR].length; ++s) {

		alert(i + ' - ' + [COLOR="#FF0000"]product[i][/COLOR][s]);
		//YOUR CODE

	}
}}

</script>

If you have other members you don't want to iterate through then we can supply a custom list instead.

garek007

yes I'll want to fill in separate tables with each group (member?) of the product object, so yes, I will hit them all. Your code is advanced and I don't quite understand it, but I'll do some reading on hasOwnProperty and come back to this post.

when you wrote this
var
product = {
system : [1],
reagents : [1, 2],
controls : [1, 2, 3],
accessories : [1, 2, 3, 4]
},

You're just declaring the object right?

bionoid

garek007;1304107 wrote:
when you wrote this
var
product = {
system : [1],
reagents : [1, 2],
controls : [1, 2, 3],
accessories : [1, 2, 3, 4]
},

You're just declaring the object right?

Yes, that was just a dummy object to show the routine displayed all values in each object member.

garek007

bionoid,

Thank you. This seems to do what I want, but I also want to understand it more. For in loops still confuse me.... Can you walk me through what is happening here?

garek007

also, do I really NEED hasOwnProperty? It seems like this would work without it since this is a custom declared object that isn't inheriting anything.

bionoid

for ( i in product ) {

FOR IN is useful for iterating through unsequential data, typically found in objects with named members.
"i" with become the index of each member as it loops, eg: system, reagents, controls, accessories.

if (product.hasOwnProperty(i)) {

hasOwnProperty was used to filter out members that the object inherited, normally defined through prototype.

bionoid

garek007;1304113 wrote:
also, do I really NEED hasOwnProperty? It seems like this would work without it since this is a custom declared object that isn't inheriting anything.

It's a precautionary measure, and it's recommended by the validator I like to use. www.jslint.com

tech_soul8

garek007;1304113 wrote:
also, do I really NEED hasOwnProperty? It seems like this would work without it since this is a custom declared object that isn't inheriting anything.

All objects inherits properties from their prototype object. Objects decleared with the object initializer expression ( {} ) use Object object as their prototype object.

garek007

ok I was able to get it to work without hasOwnProperty, but you're saying I should still use it right? as a precaution? Thanks, this worked great!

bionoid

Some frameworks that you might be inclined to use in the future could be extending the Object object, which is of course considered bad practise, but nothing stops them doing it. Then your innocent looking loop might return unexpected results.

garek007

good to know, thanks bionoid!

root

If using an array, possibly an array of objects will be better, eg.

product = [ 
    {system : [1], reagents : [1, 2], controls : [1, 2, 3], accessories : [1, 2, 3, 4] },
    {system : [1], reagents : [1, 2], controls : [1, 2, 3], accessories : [1, 2, 3, 4] },
    {system : [1], reagents : [1, 2], controls : [1, 2, 3], accessories : [1, 2, 3, 4] },
    {system : [1], reagents : [1, 2], controls : [1, 2, 3], accessories : [1, 2, 3, 4] }
];

then your Array elements are accessed via a loop as well but the object properties are then accessible, eg..

product.system

garek007

thanks \.\, I appreciate the help... but I did already get it working with the object so all is good!