Don't do that! Check this out: https://it.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval
You can use cell arrays instead
% store your data in x{k}
for k = 1:5
x{k} = myNiceTable;
end
now you have x{k} instead of xk
% then convert to array
for k = 1:5
x{k} = table2array(x{k});
end
If you really want to use variables with dynamically generated names you should make use of eval
for k = 1:5
sprintf('x%d = table2array(x%d)', k,k);
end
