CODEWITHSUNDEEP
arraysactionscript-3
Brandon Reed
Brandon Reed

Reputation: 33

Accessing Array Length comes back as Zero

I have an array in ActionScript 3 that is formatted as follows:

var _arrayList = new Array;
_arrayList["item1"] = true;
_arrayList["item2"] = 56;
_arrayList["item3"] = "john doe";
_arrayList["item4"] = -56.8;

and I'm attempting to pull the "_arrayList.Length" but it comes back 0... why?

Upvotes: 0

Views: 38

Answers (1)

Andrey Popov
Andrey Popov

Reputation: 7510

Because the way you do it makes the array "associative". In Action Script, every class is a basic Object, with dynamic properties. And array does both - containing indexed elements, and having a dynamic properties.

Here's an example of a regular array:

var array:Array = new Array();
array.push(value); // equal to array[0] = value;
array.push(56); // equal to array[1] = value;

array[20] = 'test'; // will put 20th element to be 'test'

If you use this approach, the length of the array will not be 0. And so you can use a for loop:

var total:uint = array.length;
for (var i:uint = 0; i < total; i++) {
    trace (array[i]);
}

But when the keys are not numeric, you are actually setting "properties" to the array and thus the length is 0. Again, you can loop through them, but with for-in:

for (var key:String in array) {
    trace (array[key]);
}

Here the keys won't be 0, 1, 2, 3 and so on, but instead will be item1, item2, item3. (keep in mind that the order is not preserved!)

So the basic conclusion is that if you use non-numeric keys, then use an Object instead. Array is for numeric indexed collections.

Upvotes: 1

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