var map : Object = new Object();
map[ key ] = value; 

var map : Array = new Array();
map[ key ] = value; 

mySavedValue = map[ key ]; 

var map : Dictionary = new Dictionary();

var key1 : Object = new Object();
var key2 : Sprite = new Sprite();
var key3 : UIComponent = new UIComponent();

map[ key1 ] = value1
map[ key2 ] = value2
map[ key3 ] = value3

for each ( var o1 : Object in myCollection1 )
{
    for each ( var o2 : Object in myCollection2 )
    {
        if ( o2.id == o1.relatedId )
        {
            //do something with the data that matches
            break;
         }
     }
}

var map : Object = new Object();

//first create a map
for each ( var o2 : Object in myCollection2 )
{
    map[ o2.id ] = o2;
}

//now, loop over the first collection and use the map
for each ( var o1 : Object in myCollection1 )
{   
    var foundObject : * = map[ o1.relatedId ];
    //now do something with the found object
}