Running the following code gives the classic "Dot indexing is not supported for variables of this type"

Hey all! So I'm currently running a piece of code which essentially retrieves all the trials ("myTrials") for a particular condition (referred in code as "condId") in a number of files (I'm currently loading them through a loop). I have written a function in a separate file, which on execution runs this following line of code. Note that the error occurs in this particular line.

myTrials = d.getConds()

which calls the respective function on another script. The complete script is shown as follows:

function [conds,condIds] = getConds(d)
        % Retrieves all trials for a given condID
        
          condIds = d.meta.condIds;
          [~,ix] = unique(condIds);
          tmp = d.meta.image.filename('time',Inf).data;
          conds = {};
          conds(ix) = tmp(ix); 
          myTrials = find(condIds == 1); %match all trials with conditionID = 1
end

Answer 1

[Walter Roberson]

myTrials = d.getConds()

for this to work, d can be a struct with a field named getConds that happens to be a function handle. Notice that no parameter is passed to the handle.

function [conds,condIds] = getConds(d)

But notice this requires d to be passed in, which the struct/handle possibility would not do.

So d cannot be struct.

The alternative is that d could be an object of a class, and getConds could be a method declared for the class. This is legal, under the constraints described at https://www.mathworks.com/help/matlab/matlab_oop/methods-in-separate-files.html

It is not clear from what you have written that you have implemented a class.