Merge two ArrayCollection - Flex - actionscript-3

Question

I have two ArrayCollection and I want to merge them into one...
arr1 =
[0] -> month = 07
tot_err = 15
[1] -> month = 08
tot_err = 16
[2] -> month = 09
tot_err = 17
arr2 =
[0] -> month = 07
tot_ok = 5
[1] -> month = 08
tot_ok = 6
[2] -> month = 09
tot_ok = 7
I would like to have this array
arr3 =
[0] -> month = 07
tot_err = 15
tot_ok = 5
[1] -> month = 08
tot_err = 16
tot_ok = 6
[2] -> month = 09
tot_err = 17
tot_ok = 7
How can I do it?
EDIT:
I did this solution:
private function mergeArrays(a:ArrayCollection, b:ArrayCollection):ArrayCollection
{
for (var i:int=0;i<a.length;i++)
for each(var item:Object in b)
{
if( a[i].month == item.month){
a[i].tot_err = item.tot_err;
}
}
return a;
}
But there is an important problem, if array2 (b) has a item.month that there isn't in the array1 (a) the value is lost...

Answer 1

private function mergeArrays(a:ArrayCollection, b:ArrayCollection):ArrayCollection
{
var result:ArrayCollection = new ArrayCollection();
var months:Dictionary = new Dictionary();
for (var i:int = 0; i < a.length; i++)
{
var mergedItem:Object = new Object();
mergedItem.month = a[i].month;
mergedItem.tot_ok = a[i].tot_ok;
mergedItem.tot_err = null;
for (var j:int = 0; j < b.length; j++)
{
if(a[i].month == b[j].month)
{
mergedItem.tot_err = b[j].tot_err;
}
}
month[mergedItem.month] = true;
result.addItem(mergedItem);
}
// so far we have handled all occurrences between a and b,
// now we need to handle the items from b that are left
for each (var bItem:Object in b)
{
mergedItem = new Object();
mergedItem.month = bItem.month;
mergedItem.tot_err = bItem.tot_err;
mergedItem.tot_ok = null;
if (months[mergedItem.month] == null)
{
month[mergedItem.month] = true;
result.addItem(mergedItem);
}
}
return result;
}

Answer 2

if( a[i].month == item.month){
a[i].tot_err = item.tot_err;
// remove the item from b here. dontknow arraycollection
// should be like b.remove(item);
}
after for loops you can check if "b" still have elements, so you can add them to "a", dont forget to give "b" array objects a default tot_ok value. And another thing if an object in "a" that doesnt have equalivant in "b" you can use this.
private function mergeArrays(a:ArrayCollection, b:ArrayCollection):ArrayCollection
{
var ex:Boolean = true;
for (var i:int=0;i<a.length;i++){
for each(var item:Object in b)
{
if( a[i].month == item.month){
a[i].tot_err = item.tot_err;
ex = true;
}else{
ex = false;
}
}
if(!ex){
// give a default value here.
a[i].tot_err = 0;
}
}
return a;
}

Answer 3

private function mergeArrayCollections(a:ArrayCollection, b:ArrayCollection):ArrayCollection {
var c:ArrayCollection=new ArrayCollection(b.toArray()); //clone b so as not to modify b
//This loop handles all objects common to a and b
for each(var o:Object in a) {
for (var i:int=0; i<c.length; i++) {
var p:Object=c.getItemAt(i);
if(o.month==p.month) {
//if the month is the same then add the property to a
o.tot_ok=p.tot_ok;
c.removeItemAt(i);
break;
}
}
}
//This loop adds the leftover items from c to a
for each(var q:Object in c) {
q.tot_err=-1; //add this so that all objects in a are uniform
a.addItem(q);
}
return a; //Unnecessary return, a will be modified by reference
}

Answer 4

if array2 (b) has a item.month that there isn't in the array1 (a) use addItem() method to add new object to array1 (a) ;