associative arrays; sorting, counting

[mk834tt]

When you use an object as an assc array as in:

var aa = new Array();

aa["peanuts"] = 2.50;
aa["popcorn"] = 3.50;
....

Is there a way to determine the number of entries?
So far I count this way: for (var x in aa) num_in_aa++;

How do you sort these? Is there a way to sort within the for/in
construct, something like

for(var x in 'sort aa') ????

Thanks.

[DS]

On Wed, 19 Dec 2007 19:47:19 -0800, mk834tt wrote:

When you use an object as an assc array as in:

var aa = new Array();

aa["peanuts"] = 2.50;
aa["popcorn"] = 3.50;
...

Is there a way to determine the number of entries? So far I count this
way: for (var x in aa) num_in_aa++;

How do you sort these? Is there a way to sort within the for/in
construct, something like

for(var x in 'sort aa') ????

Thanks.

FWIW, Javascript, unlike PHP, does *not* have associative arrays.
When you do the above code, you are actually creating an object aa with 2
properties, peanuts and popcorn. Thus aa.length will be zero unless you
set it yourself.
So yes, for .. in is the only way to iterate over elements, exactly like
you would iterate an object's elements.
I'll let someone else write the sorting code for you. lol

[mk834tt]

I'll let someone else write the sorting code for you. lol

That's ok. I thought there might be some special construct to sort
it. Thanks.

[AKS]

On Dec 20, 8:47 am, [e-mail] wrote:

How do you sort these?

var aa = new Array();

aa['cola'] = 4.50;
aa['something else'] = 10.02;
aa['peanuts'] = 2.50;
aa['popcorn'] = 3.50;

var arr = [];

for (var key in aa) {
arr.push([key, aa[key]]);
};

var tmp = Array.prototype.toString;

Array.prototype.toString = function () {
return this[1];
};

arr.sort(function (x, y) { return x - y; });

Array.prototype.toString = tmp;

alert(arr.join('\n').replace(/,/g, ': '));

[Thomas 'PointedEars' Lahn]

mk*****@yahoo.com wrote:

When you use an object as an assc array as in:

var aa = new Array();

aa["peanuts"] = 2.50;
aa["popcorn"] = 3.50;
...

Is there a way to determine the number of entries?
So far I count this way: for (var x in aa) num_in_aa++;

How do you sort these? Is there a way to sort within the for/in
construct, something like

for(var x in 'sort aa') ????

JavaScript 1.7 as of Gecko 1.8.1 (e.g. in Firefox 2.0) introduces iterators
that allow you to do just that:

http://PointedEars.de/scripts/es-matrix/#i
http://developer.mozilla.org/en/docs..._1.7#Iterators

Otherwise you should follow Rob's suggestion.

In addition, also because you are interested in "the number of entries", you
could construct and use a collection yourself, or use an existing
implementation, like <http://PointedEars.de/scripts/collection.js>. I have
not tested it sufficiently yet, so you might have to tweak it a bit -- any
feedback is welcome. (However, please also take note of the licensing
conditions under which it is distributed.)
HTH

PointedEars
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