ERROR: Error using {} Variable index exceeds table dimensions. How to apply function to all cells/tables?

Hi, I have a fucntion called "edit" which I want to apply to all columns of all tables in all cells in "results_velocity_diff" (see attachment).

I tried it using this code as a test:

% Get the first table from the first cell
first_table = results_velocity_diff{1, 1};

% Initialize a cell array to store the results
results = cell(1, width(first_table));

% Apply edit to each column in the first table
for col = 1:width(first_table)
    results{col} = edit(first_table{:, col}, 0, 0, 0);
end

That worked fine. But when I try and apply it to the rest of the columns in the tables of the cells using this code:

% Initialize results_edit to store the results
results_edit = {};

% Iterate through each cell array
for i = 1:numel(results_velocity_diff)
    sub_cell_array = results_velocity_diff{i};
    
    % Initialize a new sub cell array for the results
    edit_sub_cell_array = {};
    
    % Iterate through each table in the sub cell array
    for j = 1:numel(sub_cell_array)
        table_data = sub_cell_array{j};
        edit_table = table(); % Initialize an empty table to store results
        
        % Iterate through each column in the table
        for col = 1:width(table_data)
            % Apply the edit function to the current column
            edit_result = edit(table_data{:, col}, 0, 0, 0);
            
            % Store the result in the edit table
            % Creating a new variable name dynamically
            var_name = table_data.Properties.VariableNames{col};
            edit_table.(var_name) = edit_result;
        end
        
        % Store the table in the sub cell array
        edit_sub_cell_array{end+1} = edit_table;
    end
    
    % Store the sub cell array in results_edit
    results_edit{end+1} = edit_sub_cell_array;
end

Then I get the error:

Error using {}

Subscripting into a table using one subscript (as in t(i)) is not supported. Specify a row subscript and a variable subscript, as in t(rows,vars). To select variables, use t(:,i) or for one

variable t.(i). To select rows, use t(i,:).

Error in

table_data = sub_cell_array{j};

What am I doing wrong?

[lil brain]

EDIT:

I now fixed the code like this:

% Initialize results_edit to store the results
results_edit = {};

% Iterate through each cell array
for i = 1:numel(results_velocity_diff)
    sub_cell_array = results_velocity_diff{i};
    
    % Initialize a new sub cell array for the results
    edit_sub_cell_array = {};
    
    % Iterate through each table in the sub cell array
    for j = 1:numel(sub_cell_array)
        table_data = sub_cell_array{:,j};
        edit_table = table(); % Initialize an empty table to store results
        
        % Iterate through each column in the table
        for col = 1:size(table_data, 2) % Using size instead of width for double array
            % Apply the edit function to the current column
            edit_result = edit(table_data(:, col), 0, 0, 0);
            
            % Store the result in the edit table
            % Creating a new variable name dynamically
            var_name = ['Column_' num2str(col)]; % Creating generic names for double array columns
            edit_table.(var_name) = edit_result;
        end
        
        % Store the table in the sub cell array
        edit_sub_cell_array{end+1} = edit_table;
    end
    
    % Store the sub cell array in results_edit
    results_edit{end+1} = edit_sub_cell_array;
end

But now I get a new error message which I cant solve:

Error using {}

Variable index exceeds table dimensions.

Error in

table_data = sub_cell_array{:,j};

Answer 1

[Voss]

It looks like this code was written expecting results_velocity_diff to be a cell array of cell arrays of tables, but in fact results_velocity_diff is a cell array of tables.

load('results_velocity_diff')
results_velocity_diff % cell array of tables

results_velocity_diff = 3x12 cell array
  Columns 1 through 10

    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2153x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}
    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}
    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}

  Columns 11 through 12

    {2154x2 table}    {2154x2 table}
    {2154x2 table}    {2154x2 table}
    {2154x2 table}    {2154x2 table}

So you basically can remove the 2nd loop (the j loop).

% Initialize results_edit to store the results
results_edit = cell(size(results_velocity_diff));

% Iterate through each cell
for i = 1:numel(results_velocity_diff)
    
    table_data = results_velocity_diff{i};
    
    edit_table = table(); % Initialize an empty table to store results
    
    % Iterate through each column in the table
    for col = 1:width(table_data)
        % Apply the edit function to the current column
        edit_result = edit(table_data{:, col}, 0, 0, 0);
        
        % Store the result in the edit table
        % Creating a new variable name dynamically
        var_name = table_data.Properties.VariableNames{col};
        edit_table.(var_name) = edit_result;
    end
    
    % Store the table in results_edit
    results_edit{i} = edit_table;
    
end

results_edit

results_edit = 3x12 cell array
  Columns 1 through 10

    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2153x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}
    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}
    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}    {2154x2 table}

  Columns 11 through 12

    {2154x2 table}    {2154x2 table}
    {2154x2 table}    {2154x2 table}
    {2154x2 table}    {2154x2 table}

Since I don't have your edit function, I made a simple one to use here:

function out = edit(varargin)
% dummy function for demonstration, just returns the first input
out = varargin{1};
end

But really you should avoid naming a function "edit" because that's the name of an important built-in MATLAB function.

[lil brain]

Great stuff again @Voss. Works well! And yes the edit function name is subideal thats very true. Will keep that in mind.

Answer 2

[Walter Roberson]

first_table = results_velocity_diff{1, 1};
% Initialize a cell array to store the results
results = cell(1, width(first_table));

we deduce from this code that results_velocity_diff{1,1} yields a table object.

sub_cell_array = results_velocity_diff{i};

We deduce from the fact that that line worked, that results_velocity_diff is not a table itself -- if it was, then you would have gotten the complaint about 1 subscript there already. So results_velocity_diff is a cell array, and results_velocity_diff{i} is the same as results_velocity_diff{i,1} or results_velocity_diff{1,i} and so yields a table object. So sub_cell_array is a table object.

table_data = sub_cell_array{j};

And here you try to index the table object using a single subscript, which is not a permitted operation.

Possibly you want

sub_cell_array = results_velocity_diff(i, :);