Does randperm work with objects rather than integer?.

I am trying to shuffle a deck of cards and am using

function obj = shuffle(obj)
        obj.carddeck = obj.carddeck(randperm(length(obj.carddeck)));
end

yet when i print out the instance of "carddeck", each object or "card" is in the same position and there is no change

Answer 1

[Walter Roberson]

In that code, randperm is being applied to the integer length(obj.carddeck) not to some other kind of object. What-ever your problem might be is elsewhere.

You could, for debugging purposes, break out the randperm into a temporary variable, so that you could see that it is working properly; that would allow you to check that your indexing is returning a new order and that your revised obj has the new order.

My guess would be that you are calling the shuffle routine without assigning the result to the original object.

[Maya Nielan]

how do I assign the result to the original object? My working portion of the code is below up until 'end'

temp = Card.empty();
  for x = 1:52
      temp(x) = obj.carddeck(randsample(52,1));
  end    
obj.carddeck = temp;

I know the temporary variable "temp" is correctly working and holds a randomly sorted vector of "Card"s.

However reassigning my property "carddeck" using

obj.carddeck = temp;

doesn't work.

[Walter Roberson]

That version of the code uses selection with replacement, so it is not suitable for shuffling. Your original code looks fine. However, when you call the shuffle code, you cannot simply use

shuffle(MyDeck)

or

MyDeck.shuffle

and you instead need to use

MyDeck = shuffle(MyDeck)

or

MyDeck = MyDeck.shuffle

If you want to be able to use simply

MyDeck.shuffle

as the syntax, then you need to switch to handle objects instead of structures or value objects.