how to extract matrix column and make new matrixes from the extracted column?

how to extract matrix column and make new matrixes from the extracted column? if you name the column a, b, and c then i want to create matrixes which consist of

a

b

c

ab

ac

bc

abc

Answer 1

[Image Analyst]

a = fullMatrix(:, colA); % colA is whatever column number "a" is in.  It's an integer.
b = fullMatrix(:, colB);
c = fullMatrix(:, colC);
ab = fullMatrix(:, colAB);
ac = fullMatrix(:, colAC); % etc.
% Concatenate
newColVector = [a;b;c;ab;ac;bc;abc]

[eri]

i am not in front of my computer right now and there is no matlab in the computer i currently use, so i cannot try it right away

but i still have questions:

1. you wrote 'fullMatrix' is this a function in matlab or i should enter the matrix

2. it seems that your answer requires me to write a function for each combination, while actually i am going to work with a big matrix(more than 50 columns), and there would be {(2^n)-1} combination, so i would like you and other people here to give solution how to make program that will automatically create those combination

[Daniel Shub]

@eri, do you realize how big of a number 2^50 is?

Answer 2

[Walter Roberson]

Where YourMatrix is your existing matrix with all columns, and the number of columns is at most 52 (or is it 53?)

ncols = size(YourMatrix,2);
numoutputs = 2^ncols;
TheOutputs = cell(numoutputs,1);

for K = 1 :  numoutputs
  TheOutputs{K} = YourMatrix(:,dec2bin(K-1,ncols) == '1');
end

If you are enthusiastic about the leading columns being chosen first, then you can fliplr() the result of the comparison.

Do not be surprised if at the creation of TheOutputs you get an error about the size of the cell array being too big to handle. If that happens, you can comment out that line as it is just an optimization.