Dot Indexing is not supported

Hi there,

In my analysis I am running into the error "Dot Indexing is not supported for variables of this type", for the following line (shortened):

i_hclc=~cellfun(@isempty,regexp(raw.cond,contrast_select{i}{1}));

%% Contrast images for mega-analysis

contrast_select={{'High_Cal_Low_Cal',...% Floor_21
    'NaN'},...
    {'High_Cal_Low_Cal',...% Floor_16
    'NaN'},...
    {'High_Cal_Low_Cal',...% Smeets 18
     'Food_Nonfood'},... 
     {'NaN',... %Smeets_13
     'Food_Nonfood'}};

 %% Get data
subject_level_vars={'study_ID','sub_ID','gender','age','BMI',...
                    'hunger_state'};
contrast_level_vars={'sub_ID','cond'};

df.subjects=repmat({table()},4,1);

for i=1:length(df.study_ID)
    raw=df.raw{i,1}; %Get all images from current study
   
    i_hclc=~cellfun(@isempty,regexp(raw.cond,contrast_select{i}{1}));
    i_fnf=~cellfun(@isempty,regexp(raw.cond,contrast_select{i}{2}));
end

My dataframe summarises the different studies in my analysis(4x24), the column raw in dataframe is a table of the subject information within each study (Number of participants of study x 8). The latter contains the column "cond"

smeets_13.cond = repmat({'Food_Nonfood'},size(smeets_13.con_img));

Thank you for any help!

[Rik]

The error has nothing to do with regexp. It occurs when you try to do raw.cond. What is the size and data type of raw? Note that Matlab does not have a data type called dataframe. A dataframe in R is roughly equivalent to a table in Matlab (although a struct can be used for roughly the same purposes).

[Jennifer March]

Hi Rik,

Thank you for your fast response. I have a table df = 4×24 table, where df.raw= 4×1 cell array

{350×8 table }

{ 0×0 double}

{ 0×0 double}

{ 30×8 table }

In row 1 and 4 the tables are specified, wheras in 2 and 3 not yet, is that the reason for the error?

[Allen]

With your raw variable assigned in to the workspace, can you run the following and post the results?

whos ('raw')

[Rik]

That is the most likely explanation. You might consider changing your loop.

About your loop: it overwrites the results, so only the last iteration will actually be stored. You are also using length, instead of numel or size, which may lead to unintended behavior for array inputs. And personally I try to avoid i and j as variables.

[Jennifer March]

That was it! Thank you!