How to create multiple strings

The following code, I use eval to create multiple similiar matrixs

num=input('Please enter the number of rock types:');

%Setup initial ore and waste matrix respectively

for i = 1 : num
    
    eval(['M_ORE',num2str(i), ' =zeros(R1,C1)']);%multiple ore matrix
end

But I do not know how to create multiple strings

For example, the initial string is 'rn_mill_ton'

I want to input n=5, and the multiple strings such as 'r1_mill_ton', 'r2_mill_ton','r3_mill_ton','r4_mill_ton', and 'r5_mill_ton' are created.

Therefore, how to do that?

Thanks!

[Matt J]

Don't do this!!

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

Answer 1

[Jan]

Do not create variables dynamically using eval . See: TUTORIAL: How and why to avoid Eval

Hiding indices in the names of variables makes it cruel to access them later on. Use an array instead:

n = 5;
C = cell(1, n)
for k = 1:num
   C{k} = sprintf('r%d_mill_ton', k);
end

Answer 2

[Adam Danz]

Don't use eval() at all. 💀💣

• Matlab documentation: Alternative eval()
• Matlab Fandom: Why is it advised to avoid using the "eval" function?
• Lots of experienced Matlab users strongly recommend to avoid eval()
• TUTORIAL: How and why to avoid Eval

Since all of the variables you're dynamically creating are the same size (R1xC1) you're better off creating a 3D array,

num=input('Please enter the number of rock types:');
M_ORE = zeros(R1,C1,num);

So to get the matrix for rock type number j,

M_ORE(:,:,j)

[Chao Zhang]

Thank you！