add CBA_fnc_selectRandomArray

[neilzar]

When merged this pull request will:

• Adds a function that will select a specified amount of elements from an array at random without picking the same element multiple times.

Unsure if the function name is the best option, but I think it might become too long otherwise.

[commy2]

Atm. this function has inconsistent behaviour about modifying the input array by reference.

private _original = [1,2,3];
private _selected = [_original, 2] call CBA_fnc_selectRandom;

hint str _original; // []

vs.

private _original = [1,2,3];
private _selected = [_original, 10] call CBA_fnc_selectRandom;

hint str _original; // [1,2,3]

I think a function like this should not modify its arguments on the principle of avoiding side effects.

The solution would be to deep copy after the params line:

_array = + _array;

But if the array is itself made up of arrays, then it may be interesting to not copy these sub arrays as well, but to keep their references. This is an edge case, but I personally would expect that behaviour. This could be implemented easily by doing a shallow copy of the input array instead:

_array = [] + _array;

[kymckay]

@commy2 I think deep vs shallow copy behaviour should be consistent across array functions (i.e. shuffle should also do shallow if that's done here - currently it does deep).

[commy2]

OK, now all we need is a better name. selectRandom is a command that picks one element at random, so what about CBA_fnc_selectSomeRandom or CBA_fnc_selectRandomArray?

[neilzar]

I think selectSomeRandom is more descriptive. selectRandomArray can still be confused as to what the function does, it could mean that the function selects a random array from an array of arrays, for example.

[commy2]

Anyone else prefers selectRandomArray? Makes me think of inArea vs. inAreaArray, isEqualType vs. isEqualTypeArray, actionKeysNames vs. actionKeysNamesArray etc.
The only command with "Some" is someAmmo.

[dedmen]

selectRandomArray sounds like it would select a random array out of an array of arrays

[commy2]

It selects an array of elements out of an array as opposed to a single element out of an array. The name fits really well.