How to use strings to access a multi-level structure?

I have some strings look like "TestParameter.Measurement.OutputValue" and values corresponding to each string. I want to creat a structure with the strings and assign the values to the structure.

For example, if the input string is "TestParameter.Measurement.OutputValue" and the corresponding value is 3, I hope do the thing as follow through a function:

TestParameter = struct;
TestParameter.Measurement.OutputValue = 3;

Also, the level of the structure is not fixed. How can I do what I want?

Thank you!

Answer 1

[Walter Roberson]

Use setfield https://www.mathworks.com/matlabcentral/answers/1612735-have-an-error-with-dot-while-searching-value-in-struct#answer_856880

[Cheng-Yu Lin]

It works! Thank you very much!

Answer 2

[Cris LaPierre]

You can use strings to build a structure, but I don't believe you can add multiple levels at once, and I don't believe you can dynamically create the first level.

str = split("TestParameter.Measurement.OutputValue",".")

str = 3×1 string array
    "TestParameter"
    "Measurement"
    "OutputValue"

TestParameter.(str(2)).(str(3)) = 3

TestParameter = struct with fields:
    Measurement: [1×1 struct]

[Cheng-Yu Lin]

Thank you very much!

[Stephen23]

"but I don't believe you can add multiple levels at once"

Actually this is quite easy... see my answer.

Answer 3

[Stephen23]

The variable name should not be dynamically accessed:

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

Arbitrarily nested fieldnames can be accessed at once using SETFIELD and GETFIELD, for example:

S = struct();
T = 'ignorethis.Measurement.OutputValue';
F = regexp(T,'[^.]+','match'); % or SPLIT()
S = setfield(S,F{2:end},3)

S = struct with fields:
    Measurement: [1×1 struct]

Checking:

S.Measurement.OutputValue

ans = 3

More robust code would not store those nested fieldnames as one string/charvector, but as separate fieldnames.

[Cheng-Yu Lin]

It works! Thank you very much!