Automatically create variable names

Hello!

I am trying to create variable names automatically, such as:

Name_1

Name_2

Name_3

...

Name_N

To assign a different value to each one.

Do you know how to do it, any idea?

[Walter Roberson]

Why do you want to do this?

[Stephen23]

"Do you know how to do it, any idea?"

Yes, if you want to force yourself into writing slow, complex, inefficient, obfuscated code that is buggy and hard to debug:

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

The standard MATLAB approach is to use indexing. Indexing is explained in the introductory tutorials:

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

Indexing is neat, simple, and very efficient, unlike your approach. Indexing is a MATLAB superpower. If you do not learn how to use indexing, then using MATLAB will be very... difficult.

[FERNANDO CALVO RODRIGUEZ]

Ohh, okay thanks! ;) @Stephen23

I see it's a bad idea hahaha. I need to improve at code optimisation.

[FERNANDO CALVO RODRIGUEZ]

It's for connectivity matrices in Finite Element Method. @Walter Roberson

[Jan]

@FERNANDO CALVO RODRIGUEZ: Follow Stephen's valuable suggestion. Creating variables dynamically is a shot in your knee.

[John D'Errico]

There are limits of course. If you want to create two variable names, calling them x1 and x2, go for it. Maybe that makes sense. You have two points, and want to refer to them in code. Personally it is something I do. I'll admit that it is easier and faster to type x1 than to type x(1). But my limit is usually at most 2 such variables, and only when it makes some sense to have them as different variables instead of a vector.

Once you start to create whole sets of numbered names, you are going in the wrong direction. That is when it is time to start using vectors and arrays. Your code will improve by leaps and bounds when you start to do so too.

[chrisw23]

may be field names are a solution

define an empty struct

myStruct = []

and add fieldnames dynamically

myStruct.(<varName>) = myVal

[Stephen23]

@chrisw23: given the sequentially-numbered names shown in the original question, basic indexing would be simpler and much more efficient.

Answer 1

[埃博拉酱]

NameIndex=1;
Value=2;
eval(sprintf('Name_%u=%d',NameIndex,Value));

Name_1 = 2

This is possible by eval but as mentioned in the comments section, it is not recommended if there is not a very good reason.

[Stephen23]

https://www.mathworks.com/help/matlab/learn_matlab/matrices-and-arrays.html

The name "MATLAB" comes from "MATrix LABoratory", i.e. it is designed to work efficiently with arrays and indexing. Indexing is a MATLAB superpower. If you do not use indexing, then using MATLAB will be... difficult. The name "MATLAB" does not come from "lets store the data in lots and lots of separate variables and make our data harder to work with":

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