I think at some point I needed this function for something, don’t remember what for. Anyway, what this does is it makes a multidimensional array a one dimensional.

KK_fnc_arrayFlatten = { private ["_res", "_fnc"]; _res = []; _fnc = { { if (typeName _x isEqualTo "ARRAY") then [ {_x call _fnc; false}, {_res pushBack _x; false} ]; } count _this; }; _this call _fnc; _res };

So the result is ordered exactly as elements appear in the array:

_arr = [1,2,3,[4,5,6,[7,8,9]],10,11,[12,13,14]]; _res = _arr call KK_fnc_arrayFlatten; hint str _res; // [1,2,3,4,5,6,7,8,9,10,11,12,13,14]

However if you don’t much care about the order, then there is a faster way to flatten array:

KK_fnc_arrayFlattenUnordered = { _this =+ _this; { if (typeName _x isEqualTo "ARRAY") then { _this append (_this deleteAt _forEachIndex); }; } forEach _this; _this };

It is about 2 times faster. It also returns a copy, but if the copying is removed and array is modified by reference it could be even faster:

_arr = [1,2,3,[4,5,6,[7,8,9]],10,11,[12,13,14]]; _res = _arr call KK_fnc_arrayFlattenUnordered; hint str _res; // [1,2,3,10,11,4,5,6,12,13,14,7,8,9]