confusion about many, many workspace variables

Hello all, I would like to know what I can do to concatenate or otherwise combine several items in my workspace. There are approximately 3840 samples, each is coded like: S01G1D2T3, S01G1T4....etc. Basically, there are 40 subjects, each with 96 trials. Each trial is a seperate item in the workspace. Some trials may have many more rows compared to others, but all have 36 columns of data.

Is there a way by which I can concatenate all trials, or perhaps a loop that will place each item into a matrix, but not requiring me to enter each item in sequence? Thanks a heap

Answer 1

[Walter Roberson]

Please see http://matlab.wikia.com/wiki/FAQ#How_can_I_create_variables_A1.2C_A2.2C....2CA10_in_a_loop.3F

Answer 2

[Fangjun Jiang]

If you were given this data, you could do the following to improve the data structure so they are easy to handle.

save; % this saves the workspace to a default file called matlab.mat
D=load; % this loads the matlab.mat to the variable D
VarNames=fieldnames(D); % this will give you all the variable names

Then you could use a for-loop to concatenate the data. Assume all the data has 36 columns but different number of rows:

Data=[];
for k=1:length(VarNames)
Data=[Data;D.(VarNames{k})];
end

Data might grow large depending the size of your workspace data. Try some small amount of data first.