Most "MATLABesque" way to create mutable nested key value structure

Just started learning MATLAB and have a background in Python. It seems that containers.Map() is the MATLAB structure most analagous to a python dictionary object but from what I can tell it isn't really optimized for modifying nested structures. For example:

>>>test = containers.Map('food', containers.Map())
>>>test('food')('hotdog')='yummy'

Returns

Error: ()-indexing must appear last in an index expression.

While the same syntax for a non-nested structure works fine:

>>>test = containers.Map('food','hotdog')
>>>test('drinks')='beer'

I realize that MATLAB can read/write JSON files directly but that isn't a very elegant solution. What is the "correct" MATLAB data structure for storing nested key value paired data?

Answer 1

[TADA]

If you don't mind the parser restrictions on keys you can use structs, which are basically dictionaries

you can access the values using .() notation if you need to use a string:

x = struct();

x.a = 10;
x.b = 1:10;
x.c = 'blah blah blah'
    
    x = 

      struct with fields:

        a: 10
        b: [1 2 3 4 5 6 7 8 9 10]
        c: 'blah blah blah'

% now using .() notation:
x.('a') = 10;
x.('b') = 1:10;
x.('c') = 'blah blah blah'

    x = 

      struct with fields:

        a: 10
        b: [1 2 3 4 5 6 7 8 9 10]
        c: 'blah blah blah'
        
% now for nested stuff:
x.s.a = 10;
y = x.('s').('a')

    y =

        10

% invalid field names:
x.('#$%') = 10

    Invalid field name: '#$%'.
    

naturally you can use either dot indexing or .() notation to set or get whatever

Answer 2

[Walter Roberson]

fetch the nested item and store it in aa variable. Modify. Store the modified version in the top level container .

MATLAB does not generally permit indexing of the results of computation but has an exception for dot indexing of java. This is not a general exception, but {} indexing has some leeway . For example {} indexing of tables and string objects probably gets closer to computation than static addressing , but the results are indexable .