How to change the name of the display variable based on input?

I am writing a simple matlab code on multilying matrices, one of the matrices in it has elements which are a function of a parameter "theta". I want the name of the matrix (or the variable) to include that value of theta which is used to calculate those elements.

For example, in the display, i want it to show me Q_45 without me having to go and change the name manually. It should recognise that theta is 45 and hence the variable name changes to Q_45.

Please help me with this simple problem.

theta = 45;
Q_theta = [sind(theta) cosd(theta); cosd(theta) sind(theta)]

Q_theta = 2×2

0.7071 0.7071 0.7071 0.7071

[Dyuman Joshi]

Dynamically naming variables is strongly not recommended - TUTORIAL: Why Variables Should Not Be Named Dynamically (eval)

[Les Beckham]

One of the recommended ways to keep the parameter together with the data that depends on that parameter is to put them together in a structure. If there are multiple values of the parameter, you can have a structure array. For example:

theta_values = [30 45 60];
for k = 1:numel(theta_values)
    theta = theta_values(k);
    Q_theta = [sind(theta) cosd(theta); cosd(theta) sind(theta)];
    results(k) = struct('theta', theta, 'Q_theta', Q_theta);
end
results

results = 1×3 struct array with fields:
    theta
    Q_theta

[results.theta]

ans = 1×3

30 45 60

results(1).Q_theta

ans = 2×2

0.5000 0.8660 0.8660 0.5000

Note that, using this approach, your code (e.g., variable names) doesn't depend on the parameter values. So, you can change those values and re-run your code without having to edit the code.

[Stephen23]

"I am writing a simple matlab code on multilying matrices... For example, in the display, i want it to show me Q_45 without me having to go and change the name manually. It should recognise that theta is 45 and hence the variable name changes to Q_45."

That bad data design is the start of your problems.

When you stick meta-data into your variable names like that you make accessing that data slow, complex, inefficient, fragile, and much harder to debug. Best avoided.

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

"Please help me with this simple problem."

Use arrays! For example: one simple vector of those values, an ND array or cell array of those matrices, and then some very basic indexing. Do not make your code more complex than that!

[Srikar V.S]

Thank you for the suggestions!

[Stephen23]

@Shreeya: why did you delete your answer?