Printing string as a variable

I have a table (mytable)with 'm' rows and I am trying to add multiple empty columns with names that are in ascending numerical order (variable_01var, variable_02var etc) :

for i = 1:16
    number = sprintf('%02d',i);
    variable = insertAfter('mytable.variable_var', '_', number)
    sprintf(variable) = zeros(m,1);
end

I am not sure how to get the generated variable name printed as a variable though?

Any help much appreciated, thanks!

Rob

[Rik]

Are you using the data type table, or are you calling your matrix a table?

What you are looking for is the function eval, but DON'T DO THIS. You can see a discussion on why using eval is bad here or a more recent one here.

I would advise you to think what it is you want to do, because it sounds like the table data type has what you need. (on older releases it is not available)

[rob]

Thanks Rik, I am using the data type 'table'. Would you be able to advise how to do this? I.e. how to generate a set of columns with names defined in a for loop?

[Stephen23]

" I am trying to add multiple empty columns with names that are in ascending numerical order (variable_01var, variable_02var etc)"

Do NOT do this.

Read what the MATLAB documentation has to say about this: "A frequent use of the eval function is to create sets of variables such as A1, A2, ..., An, but this approach does not use the array processing power of MATLAB and is not recommended. The preferred method is to store related data in a single array"

source: https://www.mathworks.com/help/matlab/matlab_prog/string-evaluation.html

You should also read this:

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

and after that keep your data in one array and use indexing, or use a table.

Answer 1

[Rik]

If your table is called mytable, you can create a new column the same way as you can add a field to a struct:

for i = 1:16
    number = sprintf('%02d',i);
    variable = insertAfter('variable_var', '_', number)
    mytable.(variable) = zeros(m,1);
end

And why not use this:

for i = 1:16
    variable = sprintf('variable_%02dvar',i);
    mytable.(variable) = zeros(m,1);
end