how to assign a variable using a string

I have a set of variables called "error1", "error2", etc.

Each is a 4D matrix and I want to extract certain parts of them for comparison, for example I'd like to plot the vector mean(errori(1,:,1,1)), where i = 1,2,...

How can I do this? I've tried using

for i = 1:10
    a = sprintf('error%s',num2str(i));
    b(i) = mean(a(1,:,1,1));
end

But that just sets a equal to a string, not the actual variable! Is there some function I can use that makes MATLAB recognise a string as a variable with the same name?

Thanks Mike

Answer 1

[Walter Roberson]

Don't do that!

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

[Ahmed A. Selman]

The task was (how to assign a variable using a string). I not sure if the question mentioned (using cells) anywhere?!

[Walter Roberson]

Q: "I want to learn how to cut glass so I can unlock this door that I can't push open!"

A: "Did you try pulling it instead?"

Showing people alternatives to avoid their problems in the first place is a valid answer.

Besides, FAQ does show the (not-recommended!) eval() solution.

Answer 2

[Ahmed A. Selman]

Try (genvarname) with (eval) functions. Example (alter the example below to your use, i.e., instead of eval([b]) use eval([b = 'some_function(i)']) ):

clear 
clc
error1=eye(3,3);
error2=eye(3,3)*2;
error3=eye(3,3)*3;
  for i = 1:3
   a = sprintf('error%s',num2str(i));
   b = genvarname(a);
   eval([b])
  end

.. etc.

[Jan]

Do not use the EVAL approach. You find too many people here in the forum who got too many problems by this.