comparing arrays

[ljonny18]

Hi,

I have 2 arrays that I want to compare:

var a1:Array = new Array(2,1,3,0);
var a2:Array = new Array(0,2,3);

I want to compare the values in the arrays, and all the values that exist in a1 and dont exist in a2 (in this case 1 and 4), I want to put into a new array (a3):

a3 = (1,4)

how can I do this in AS3???

Thanks,
Jon.

[flexy]

I think you'd need to iterate through your arrays:


private function matchArrays( a1:Array, a2:Array ) :Array
{
var a3:Array = new Array();
var len1:int = a1.length;
for( var i:int = 0; i<len1; i++ )
{
var len2:int = a2.length;
for( var j:int = 0; j<len2; j++ )
{
if( a1[i] == a2[j] )
{
a3.push( a1[i] );
break;
}
}
}
return a3;
}

[ljonny18]

that is what I tried and was having problems with :(

in your example a3 = 2,3,0, and I only need to return the values that are in the first array and not in the second array etc....

e.g.

a1:Array = new Array(2,1,3,0);
a2:Array = new Array(0,2,3);

so I need a2:Array = new Array(1); - as "1" is tha value that is in the first array but not in the second.

Thanks,
Jon.

[flexy]

How about?


private function matchArrays( a1:Array, a2:Array ) :Array
{
var a3:Array = new Array();
var len1:int = a1.length;
var notFound:Boolean = false;
for( var i:int = 0; i<len1; i++ )
{
if( notFound )
{
a3.push( a1[i-1] )
notFound = false;
}

var len2:int = a2.length;
for( var j:int = 0; j<len2; j++ )
{
if( a1[i] == a2[j] )
{
notFound = false;
break;
}
else
{
notFound = true;
}
}
}
return a3;
}

[Jim Freer]

private function aNotInB
( avArrayA :Array,
avArrayB :Array )
:Array
{
var lvArray:Array = [];

for each( var avObjectA:Object in avArrayA )
{
if( avArrayB.indexOf( avObjectA ) == - 1 )
lvArray.push( avObjectA );
} // for each

return lvArray;

} // aNotInB

http://freerpad.blogspot.com/

[ljonny18]

thats great - thanks to both of you.

I used something similar to "Jim Freer's" example in the end

cheers guys,

Jon.

[flexy]

Yeh Jim's for...each is a better way of doing it.

[likhim]

May I know how to compare two arraycollection and return the result as arraycollection?

[randygland]

it's nice to see the logic of the longer version though, I find it easier to follow, even if it's less clean. :)
likhim, I need to do the same.. and will probably end up doing it by stripping relevant data from the ArrayCollections I want to compare into new Arrays.. comparing those arrays with Jim's for each function, then reconstructing the ARrayCollections with the results.

I will post the code.