You're almost certainly better off re-structuring your data so that you don't have to iterate through the variables in your workspace. Try storing the values in a sequential array instead.
However, if you REALLY want to do this, you can do as follows:
variables = who;
for i = 1:length(variables)
eval('A = ', variables{i}); %A now stores the i-th variables info
%do stuff to A like A > x or whatever
end
Again, don't do this! It's a bad idea. Restructure your code so you can just loop instead without using eval and dealing with the workspace.
