How to create a matrix of numbers from workspace variables?

I have 70 double variables of size 1500x1(let's call them a1,a2....a70) loaded in workspace. I would like to create a matrix M which contains these variables as columns, so that the matrix size will be 1500x70. Is there an efficient way to do this?

[Aniket Vagha]

I used this:

params = who('a*'); % Vars I need start with a.
Matrix = zeros(1500, 70); % 1500 and 70 obtained from array sizes.

for ii = 1:length(Params)

     Matrix(:,ii) = eval(Params{ii})

end

Is there a more direct way by-passing eval?

Answer 1

[Stephen23]

Yes there is an efficient way to do this: don't create 70 numbered variables in your workspace.

How did you "create" them?

If it was by load, then simply call load with an output argument:

S = load(...)

If you created your 70 variables some other way then let us know and we can show you a much better way of programming.

Read my answer to know why accessing 70 variables in a loop is slow, buggy, and obfuscated way to program:

http://www.mathworks.com/matlabcentral/answers/196952-how-to-create-new-variables-in-batches-with-strcat