MATLAB: Is there any way to convert variables from list to arrays

cell2numstr2num

I have 2 arrays

a = [1 2 3]
b = [2 3 4]

and a list

c = {'a', 'b'}

when I use cell2mat(c(1,1)), I get a, but what I want is [1 2 3]. Is there any way to achieve it?

Best Answer

Simply store the data in one structure, and then it is trivially easy (no slow, buggy eval is required):

>> S.a = [1,2,3];
>> S.b = [2,3,4];
>> C = {'a','b'};
>> S.(C{1})
ans =
   1   2   3

Simpler code through better code design: faster, neater, simpler, more efficient, easiest to debug, less complex. Why waste your time learning bad ways to write code?:

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

Related Solutions

MATLAB: How to write a1=1;a2=2;a3=3; from A

Do NOT do this

This would actually be horribly slow, pointlessly complex, obfuscated, and very buggy way to write your code. You would make your code hard to debug, and a pain to work with. Read this to know why:

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

Using indexing would be simple, neat, and very efficient. You should use one array and indexing. Indexing is the solution you should be using, because it is the most efficient way to write MATLAB code, is simple, neat, and very easy to debug. Indexing is explained quite well in the MATLAB introductory tutorials, which are highly recommended for all beginners:

https://www.mathworks.com/help/matlab/getting-started-with-matlab.html

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.

Best Answer

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MATLAB: How to write a1=1;a2=2;a3=3; from A

MATLAB: Concatenate arrays within a loop,

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