Finding What Object Is In The Array (AS3)

Question

So here's what I'm trying to do in pseudocode:

array = new Array();
thisObj = new objectTypeOne();
thisObj2 = new objectTypeTwo();
array.push(thisObj);
array.push(thisObj2);

for( i=0; i<=array.length, i++)
{ 
  if( array[i] == objectTypeOne() )
  {
    //do code
  }
 }

I know I could have two different arrays for each object type but that would ruin a lot of my other code which assumes they're both in the same array. (they are pratically same object with slight but vital differences, I suppose I should really have objectTypeTwo derive from other, but that's irrelevant at the moment).

I don't understand, what exactly do you want to do? You need to find what object type is current object when you loop through array? You can use if (array[i] is objectTypeOne) //code — randomUser56789
– randomUser56789, Commented Jan 17, 2012 at 9:25
See the last comment I made to you on my answer. It means you have an undefined reference pushed into your array... which shouldn't happen but you can account for these things with a little error checking to deal with them at runtime. — user562566
– user562566, Commented Jan 17, 2012 at 9:44

score 1 · Accepted Answer · 2012-01-17 09:32:43Z

1

I believe what you're looking for is:

if(array[i] is MyObjectType) {
   //I found an instance of MyObjectType
}

The operator "is" does runtime type analysis and will return true if the object you are testing (in this example, array[i]) is either directly of the type you're comparing to or a subclass (in this example, MyObjectType). You might also want to investigate using typeof. However, try to avoid having a TON of calls like this or calls using "typeof"... looking up type information at runtime is costly in any language.

edited Jan 17, 2012 at 9:32

answered Jan 17, 2012 at 9:21

user562566

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6 Comments

user562566 Over a year ago

P.S. - I can see you're still pretty new so welcome to StackOverflow. :)

R Bowen Over a year ago

Thanks for your descriptive answer (and thank you, I'm loving StackOverflow so far). I just have one error:

R Bowen Over a year ago

If I use: if(array[i] is Object()) It says: Incorrect Arguments, Expected one. If I use: if(array[i] is Object) It gives error "term is undefined and has no properties" at runtime

user562566 Over a year ago

That's weird.... unless you have a reference in the array that is undefined, which is possible. Try changing the if statement to if(array[i] != undefined || array[i] is Object).

R Bowen Over a year ago

Nope still says something is undefined :S

|

Diode · Accepted Answer · 2012-01-17 09:51:43Z

First correct this i<=array.length to i<array.length. That is the reason for "term is undefined" error.

The solution suggested by @Ascension Systems can be used when you create the instance of diffrent Classes, like

array = new Array();
thisObj = new Student();
thisObj2 = new Employee();
array.push(thisObj);
array.push(thisObj2);

then you can check like

for( i=0; i<array.length, i++)
{ 
  if( array[i] is Student )
  {
    //do code
  }else if(array[i] is Employee){

  }
}

If you are using custom Objects, do like this

array = new Array();
thisObj = new Object();
thisObj.type = "type1";
....
....
thisObj2 = new Object();
thisObj2.type = "type2";
...
...
array.push(thisObj);
array.push(thisObj2);

for( i=0; i<array.length, i++)
{ 
  if( array[i].type == "type1" )
  {
    //do code
  }else if( array[i].type == "type2"){

  }
}

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