Can one dynamically add new keys to a Maps data structure in Matlab?

I recently discovered the maps data structure but it seems I can't dynamically assign new keys to it. I am going through some files and don't know the keys beforehand (unless I loops through everything first to get the keys and then again to get the data). Is it possible to not have to loop through things twice and just instead add new keys as I discover them?

[note this is easy to do in python with a dictionary with `dictionary[new_key] = data` ]

[Muhammad Shaban]

Adding a new key-value pair is same as python e.g map_variable(new_key)= data.

Answer 1

[Steven Lord]

That should work if you do it as is shown by the last example on the containers.Map documentation page. Can you show the full error message (everything in red) you receive when you try? That may show us why it's not working or suggest a further avenue for investigation.

[Brando Miranda]

why can't be mixed type?

[Brando Miranda]

how do you specify that the second type is a vector/matrix type?

[Brando Miranda]

I want to map doubles to just tensors.

[Brando Miranda]

error:

Mtests = 

    Map with properties:

          Count: 0
        KeyType: double
      ValueType: double

Error using containers.Map/subsasgn
Specified value type does not match the type expected for this container.

Error in collect_flatness_results (line 19)
    Mtests(noise) = all_test_accs;

[Brando Miranda]

ok 'any' is the solution:

Mtests = containers.Map('KeyType','double','ValueType','any')

[Steven Lord]

What does class return when called on the variables noise and all_test_accs on line 19 of collect_flatness_results?

[Brando Miranda]

Steven, I think I solved it, if you put 'any' Maps can hold any type. The variables there are double and the other is an array of doubles. Thanks! :D