Indexing or appending numerical variables

I have many matrix variables like G1, G2... I want to create a loop that new variables chance their name. For example,

for i=1:32 in first step when i=1 >> M=G1 second step when i=2 >> M=G2 ... and so on.

How can I make "i" recognizable for G matrices?

Answer 1

[Star Strider]

You can do that using the eval function, and this seems a valid use for it. I would create ‘M’ as a cell array, and then assign elements of ‘M’ in a loop.

Example:

N = ...;                                % Number Of Matrices
for k = 1:N
    M{k} = eval(sprintf('G%d', k));
end

You can then address individual elements of ‘M’ in the rest of your code. See the documentation on Cell Arrays for details on how to use them if you are not familiar with them.

NOTE — This is UNTESTED CODE. It should work, probably with modifications.

[Star Strider]

Feyza Sakil’s ‘Answer’ moved here:

I tried your code, it says: "Cell contents assignment to a non-cell array object."

[Star Strider]

I have no idea what your ‘matrix variables’ are, since you have not described them.

Try this:

N = ...;                                % Number Of Matrices
for k = 1:N
    M(k) = eval(sprintf('G%d', k));
end

The change replaces the curly brackets ‘{}’ with parentheses ‘()’.

[CaptainS]

already tried.. :(

[CaptainS]

In an assignment A(I) = B, the number of elements in B and I must be the same.

Error in eval (line 3) M(k) = eval(sprintf('G%d', k));

[Star Strider]

I do not understand the reason my original Answer (using the cell array) did not work. It should work with numeric arrays, cell arrays, character arrays, structures and everything else I can think of.

Please save some (or all) of your ‘G1’, ‘G2’, matrices to a ‘.mat’ file, and use the ‘paperclip’ icon to upload them here. I cannot solve this without having access to at least some of them. (See the documentation on the ‘save’ function for information on creating a ‘.mat’ file with them if you have not used them before.)