MATLAB question: N-combinations of sections of arrays

Catharz

So I've got a 2x4 matrix which I want to use to generate a larger matrix consisting of all 2-combinations of the 4 2x1 portions of the 2x4 matrix.

Example with 2x3:

[A X]
[B Y]
[C Z]

Which I want to turn into, using nchoosek()

[A X B Y]
[A X C Z]
[B Y C Z]

Or at least generate three seperate arrays with the same information, which I can then vertically concatenate.

Unfortunately, nchoosek() will only operate on individual elements. So, I tried to set the pairs of elements equal to variables, and then use an array of those variables:

I = [A X]
J = [B Y]
K = [C Z]

...and then using nchoosek on:

[J]
[K]

Unfortunately, this just evaluates to the original 2xN array.

I then tried making the 2x1 arrays into strings, combining them them, and then re-evaluating them the the original values. Unfortunately, nchoosek doesn't work on string arrays for some reason.

So, any ideas of how I can force Matlab to not evaluate the variables, combine sets of elements, or do N-combinations of strings?

Thanks.

shwaip

check the matlab help for "cell" and let me know if you need any more help than that. You'll want to add I,J,K to a cell array and call nchoosek on the cell array.

Catharz

That worked perfectly. Thanks for the help.

I did, however, also run into an error trying to name my string cells with the following bit of code:

for i = 1:numberOfBets
    strcat('pWP',num2str(i)) = cellstr(mat2str(cat(2,bookiePayoffs(1,i)',expertProbabilities(1,i)')))
end

Can I not do an assignment or equality like that? Both sides of the equality evaluate fine individually, but when I set them equal to each other I get a 52x52 array with the correct data strewn among a field of zeros.