Assigning an iterative variable a script

Does anyone know how I can assign an iterative variable in a for loop a script value. I am trying to make a poker game in MatLab and when I try to assign suits in a for loop it doesn't work and it instead assigns them NAN. I know I could just make my suit vector a collection of 1,2,3,and 4 and then later assign those values to the suit name, but is there any way i could do it directly in the for loop? The following code is where the issue is (in the for loop, but I included the other code, so it would be simpler to understand). (I know spaids is spelled spades I need to go through and fix it)

deck=[2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 6 6 6 6 7 7 7 7 8 8 8 8 9 9 9 9 10 10 10 10 11 11 11 11 12 12 12 12 13 13 13 13 14 14 14 14];

players=input('How many players would you like to play with (max number of players is 5) ');

while players>5 | players<1 | round(players)~=players

players=input('ERROR INPUT AN INTEGER BETWEEN 1 and 5. How many players would you like to play with (max number of players is 5) ');

end

% initializing variables that will be used later

n=0;

folded=zeros(length(players));

order=randperm(52);

suit1=zeros(length(players));

suit2=zeros(length(players));

card1=zeros(length(players));

card2=zeros(length(players));

% creating the vector for the suits of the cards

suits=["spaids","hearts","clubs","diamonds","spaids","hearts","clubs","diamonds","spaids","hearts","clubs","diamonds","spaids","hearts","clubs","diamonds","spaids","hearts","clubs","diamonds","spaids","hearts","clubs","diamonds","spaids","hearts","clubs","diamonds","spaids","hearts","clubs","diamonds","spaids","hearts","clubs","diamonds","spaids","hearts","clubs","diamonds","spaids","hearts","clubs","diamonds","spaids","hearts","clubs","diamonds","spaids","hearts","clubs","diamonds"];

% assigning individual players cards

for i=1:players

n=n+1;

card1(i)=deck(order(i));

card2(i)=deck(order(i+players));

suit1(i)=suits(order(n));

suit2(i)=suits(order(n+players));

fprintf('Player %1.0f your cards are %1.0f %s and %1.0f %s\n',i,card1(i),suit1(i),card2(i),suit2(i))

end

[Voss]

Note that if players is a scalar (which I think it's intended to be), then length(players) is 1, so instead of pre-allocating like this:

card1=zeros(length(players)); % makes card1 a scalar

pre-allocate like this:

card1=zeros(1,players); % makes card1 a vector of size 1-by-players

Also, n is always the same as i, so just use i.

Also, i and the elements of card1 and card2 are all integers, so you can use %d format instead of %1.0f, but it would be interesting to figure out how to display the names of face cards, i.e., Jack, Queen, King, Ace instead of 11, 12, 13, 14 (in which case the cards printed there are no longer necessarily integers or even numeric).

[Tim Keegan]

you are right thank you for some reason it wasn't messing up the function of the code, but it was wrong. I am still working on trying to get the display the names of face cards. I think I just have to do a lot of if loops.

[Voss]

"for some reason it wasn't messing up"

That's because, if you assign to an element of an array that's off the end of the array, MATLAB will extend the array automatically (or if the array doesn't exist yet, MATLAB will allocate it to the size required):

% card1 doesn't exist yet, so MATLAB creates it and 
% gives it 5 elements, with the first 4 being 0
card1(5) = 7

card1 = 1×5

0 0 0 0 7

or similarly for a string array:

suit1(3) = "spade"

suit1 = 1×3 string array
    <missing>    <missing>    "spade"

so, pre-allocation is not strictly necessary, but it's a good idea. When you were allocating your variables to be of size 1 and then assigning elements 2, 3, etc., it's no problem, just not optimal and not what was apparently intended.

Similarly, the other things I pointed out are not problems per se, just pointers to simplify or clarify the code.

Two other things you may find useful: repelem and repmat.

deck = repelem(2:14,1,4)

deck = 1×52

2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 6 6 6 6 7 7 7 7 8 8 8 8 9 9

suits = repmat(["spaids","hearts","clubs","diamonds"],1,13)

suits = 1×52 string array
    "spaids"    "hearts"    "clubs"    "diamonds"    "spaids"    "hearts"    "clubs"    "diamonds"    "spaids"    "hearts"    "clubs"    "diamonds"    "spaids"    "hearts"    "clubs"    "diamonds"    "spaids"    "hearts"    "clubs"    "diamonds"    "spaids"    "hearts"    "clubs"    "diamonds"    "spaids"    "hearts"    "clubs"    "diamonds"    "spaids"    "hearts"    "clubs"    "diamonds"    "spaids"    "hearts"    "clubs"    "diamonds"    "spaids"    "hearts"    "clubs"    "diamonds"    "spaids"    "hearts"    "clubs"    "diamonds"    "spaids"    "hearts"    "clubs"    "diamonds"    "spaids"    "hearts"    "clubs"    "diamonds"

[Tim Keegan]

thank you for the help

Answer 1

[Jon]

The problem is that you preallocated suit1, and suit2 as a vector of doubles (numeric values), but then in the loop you assign strings to the individual elements

[Jon]

You should instead preallocate using strings, as for example

suit1=strings(length(players),1);

Note, I think your original code also has errors preallocating suit1, suit2,card1 and card2 where you set them equal to zeros(length(players)). This will create length(players) by length(players) matrix of zeros. I think you just wanted a vector. So for a column vector preallocate card1 and card 2 using zeros(length(players),1), and for the suits use strings(length(players),1) as shown above

[Tim Keegan]

Thank you this worked. I had tried doing it without preallocating at all and it hadnt worked, but this worked.