Add values to Array without setting X and Y

[Boba Fonts]

I need to add values to an array as long as they show up in the game, but not at specific X,Y, I just need them to be added at the bottom of the "list" (actually I want the array to behave as a multiple global list object). Those values must be stored in one of the four columns - in this little picture I've labeled them with string titles but I don't necessarily need them to be "keys" of the Associative Array, those could be just numeric X 1, 2, 3, 4, so maybe the whole thing can be done with the normal Array Object.
array.gif
Basically, every "column" must behave as an independent list. I need to add values to the bottom of a specific X column, whatever the last Y "coordinate" is. If I use the action "Add 1 to Y dimension index" a new line is added to the bottom of the whole array "grid", not only to one column. How can I tell it to "search for the bottom value of a specific X column and then, if exists and is empty, store a value OR first add a new line and then store the value" ?
thanks

[SolarB]

Have you tried the Dynamic Array object? It has an 'append' function.

[ChrisBurrows]

Using the normal Array Object, you can simply run a loop to find the first empty slot.

I've made you an example.

[Fanotherpg]

You van just use 4 arrays one per column.

[ColdFire]

MMF2 array and list objects are good if you want save strings into it but if You want save int, double or float you can't use it becouse You need converted it into string and this is very slow. I will relase List object for numbers this should slove Your and some of my problems.

[Boba Fonts]

Thanks to you all and to Chris for the example file. Never tried the Dynamic Array before. I've used -as a temporary solution- 4 different normal arrays, one per column, just as Fanotherpg suggested. If I choose not to change what I've already done, could multiple arrays slow down the game? Now I have a total of 7 arrays for a great number of bonuses, weapons, data, etc.

[ChrisBurrows]

I doubt using 7 arrays will have any noticeable effect on the performance of your game. As for re-writing your code to use one single array, it depends on what you are trying to do; learn more efficient programming techniques or simply make the games you want. Both are very acceptable.

[Boba Fonts]

Your mfa example is brilliant and I'm learning a couple of tricks right now!