MATLAB: Concatenation of few matrix with a loop

for loopmatrix manipulation

C{1} = [total1979_125_30];

C{2} = [total1980_125_30];

C{3} = [total1981_125_30];

C{4} = [total1982_125_30];

C{5} = [total1983_125_30];

…upto C{40} = [total2019_125_30];

just help me making the loop

So that I can use

A = cat(3,C{:});

M = mean(A,3);

Best Answer

It was not a good idea to create a variable name like this: https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval. Always use a cell array. Since you already created these, you can use the following loop to create the cell array now.

C = {};
vals = 1979:2019;
for i = 1:numel(vals)
    [~, C{i}] = evalc(sprintf('total%d_125_30', vals(i)));
end

Related Solutions

MATLAB: Concatenate arrays within a loop,

Easy, given any number of arrays in a cell array C. You could use a loop like this, although it is inefficient because the output array is not preallocated:

C = {[1,2],[3,4],...} % cell array of arrays.
A = C{1};
for k = 2:numel(C)
    A = [A;C{k}];
end

Simpler and more efficient would be to concatenate them all at once, without a loop, e.g.:

A = vertcat(C{:})

Whatever you do, do NOT try to access variable names dynamically in a loop! Read this to know why:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

Using an array (e.g. a cell array) and indexing is much simpler, neater, much more efficient, less buggy, and easier to debug.

MATLAB: Averaging Every Element of some matrices

The simple answer is to concatenate all of your matrices into one array, and then use mean. Of course all of your matrices should be in one cell array, because that makes them much easier to work with:

C{1} = [..];
C{2} = [..];
..
C{40} = [..];
A = cat(3,C{:});
M = mean(A,3)

Best Answer

Related Solutions

MATLAB: Concatenate arrays within a loop,

MATLAB: Averaging Every Element of some matrices

Related Question