How can I get around 'Matrix index is out of range for deletion' error in my case?

Hello Everyone,

I am trying to delete 49 fields on matrix, yet I get the following error message:

Matrix index is out of range for deletion.

Error in ExperimentalDataPlotting (line 56)
        fields([1,23,24,25,26,27,29,...

I have tried to follow the following examples:

https://www.mathworks.com/matlabcentral/answers/513605-error-message-matrix-index-is-out-of-range-for-deletion

https://www.mathworks.com/matlabcentral/answers/347471-i-have-this-error-msg-matrix-index-is-out-of-range-for-deletion-error-in-tray1-line-31-x1

https://www.mathworks.com/matlabcentral/answers/130875-matrix-index-is-out-of-range-for-deletion

The code I am using is:

        %% Initialize and read data from Excel
clc
clear
clf

% Read table
RawData = readtable('ExperimentalDatabaseWithoutEmptyCells.xlsx','Range','A1:CF88');

%% Chips experiments

%  Create a structure for Chips Experiment and call it "Chips",
%  Name fields "field_names" with names that corresponds to "extraction_pressure"
%  namely: Chips.Entrapped_0 corresponds to free liquor;
%          Chips.Entrapped_1 corresponds to liquor at extraction pressure of 2.5 tons;
%          Chips.Entrapped_2 corresponds to liquor at extraction pressure of 5 tons;
%          Chips.Entrapped_3 corresponds to liquor at extraction pressure of 8 tons;

extraction_pressure = [0, 2.5, 5, 8];
field_names = {'FreeLiquor','Entrapped_1','Entrapped_2', 'Entrapped_3'};

% Cycle over different extraction pressures
for l = 1:length(extraction_pressure)
    
    % Create a variable "Temp" which corresponds to the subset of data
    % entries labelled as "Chips" with a specified extraction pressure
    Index = find(strcmp(RawData.ParticleSize, 'Chips') ...
                  .* ( RawData.EntrappedLiquorSqueezing_tons_ == extraction_pressure(l) ) );
    Temp = RawData(Index,:);
    
    % Write the "Cooking Time" into a vector
    Chips.(field_names{l}).Time = Temp.CookingTime_min_;
    
    % Extract all the data that stays constant for a particular experiment
    % with chips, and save this into a "Description" structure.
    Chips.(field_names{l}).Description = struct(  'T', Temp.CookingTemperature__C_(1), ...
                                                  'P', Temp.CookingPressure_bar_(1), ...
                                                  'WoodMass', Temp.WoodMass_g_(1), ...
                                                  'SteamMass', Temp.SteamMass_g_(1), ...
                                                  'Na2SO3ODWBasis', Temp.Na2SO3ODWBasis___(1), ...
                                                  'Na2CO3ODWBasis', Temp.Na2CO3ODWBasis___(1));

    % Remove redundant variables from "Temp"
    Temp = removevars(Temp, {'Date', 'Run_', 'CookingTime_min_', ...
                             'CookingTemperature__C_', 'CookingPressure_bar_', ...
                             'WoodMass_g_', 'SteamMass_g_','ParticleSize', ...
                             'Na2SO3ODWBasis___','Na2CO3ODWBasis___', ...
                             'EntrappedLiquorSqueezing_tons_','ID_'});

    % Find all of the remaining fieldnames (TDS, LiquorPH, etc) and save
    % the field names into a cell array "fields". 
    fields = fieldnames(Temp);
    
% Remove fields that will not be plotted
    % fields ([1, 21, 22, 23]) = [];
        fields([1,23,24,25,26,27,29,...
                30,31,34,35,36,38,39,...
                40,41,43,44,45,46,48,49,...
                50,51,53,54,55,56,58,59,...
                60,61,63,64,65,66,68,69,...
                70,71,73,74,75,76,78,79,...
                80,81,83]) = [];
    
    % Find all the data entries that have a value of "0" for the repeat.
    % This will always be the first data entry for a specific time point
    Rep0 = find(Temp.Repeat_ == 0);
    for i = 1:length(Rep0)
        % Find all the repeats associated with the current cooking time
        k = find(Chips.(field_names{l}).Time == Chips.(field_names{l}).Time(Rep0(i)));
        
        % Save the relevant data to the "Chips" structure.
        % Recall that field_names = {'FreeLiquor','Entrapped_1',...}
        % So Chips.(field_names{l}) will correspond to Chips.FreeLiquor when l = 1
        % We now create three fields:
        %    Chips.(field_names{l}).Repeats - cell array containing
        %       individual values from each repeat, e.g.
        %       Chips.FreeLiqour.Repeats.TDS = {[0.8606], [0.7753, 0.9610, 0.8663], ...}
        %
        %    Chips.(field_names{l}).Mean - array containing mean values
        %       over repeats, which is useful for plotting vs Time
        %
        %    Chips.(field_names{l}).STD - array containing standard
        %    deviations over repeats, which is useful for plotting errorbars
        for j = 1:length(fields)
%             Chips.(field_names{l}).Repeats.(fields{j}){i} = Temp.(fields{j})(k);
            try 
                Chips.(field_names{l}).Mean.(fields{j})(i) = mean(Temp.(fields{j})(k));
                Chips.(field_names{l}).STD.(fields{j})(i) = std(Temp.(fields{j})(k));
            catch

            end
        end
    end
    
    % Remove redunandant time points
    Chips.(field_names{l}).Time = unique(Chips.(field_names{l}).Time);
    
end

%% Fines Experiments

%  Create a structure for Fines Experiment and call it "Fines",
%  Name fields "field_names" with names that corresponds to "temperature"
%  namely: Fines.Temp_161 corresponds to a temperature of 161 °C;
%          Fines.Temp_170 corresponds to a temperature of 170 °C;
%          Fines.Temp_179 corresponds to a temperature of 179 °C;
%
temperature = [161, 170, 179];
field_names = {'Temp_161','Temp_170','Temp_179'};

% Cycle over different temperatures
for l = 1:length(temperature)
    
    % Create a variable "Temp" which corresponds to the subset of data
    % entries labelled as "Fines" with a specified temperature
    Index = find(    strcmp(RawData.ParticleSize, 'Fines') ...
                  .* ( RawData.CookingTemperature__C_ == temperature(l) ) );
    Temp = RawData(Index,:);
    
    % Write the "Cooking Time" into a vector
    Fines.(field_names{l}).Time = Temp.CookingTime_min_;
    
    % Extract all the data that stays constant for a particular experiment
    % with fines, and save this into a "Description" structure.
    Fines.(field_names{l}).Description = struct(  'P', Temp.CookingPressure_bar_(1), ...
                                                  'WoodMass', Temp.WoodMass_g_(1), ...
                                                  'SteamMass', Temp.SteamMass_g_(1), ...
                                                  'Na2SO3ODWBasis', Temp.Na2SO3ODWBasis___(1), ...
                                                  'Na2CO3ODWBasis', Temp.Na2CO3ODWBasis___(1));

    % Remove redundant variables from "Temp"
    Temp = removevars(Temp, {'Date', 'Run_', 'CookingTime_min_', ...
                             'CookingTemperature__C_', 'CookingPressure_bar_', ...
                             'WoodMass_g_', 'SteamMass_g_','ParticleSize', ...
                             'Na2SO3ODWBasis___','Na2CO3ODWBasis___', ...
                             'EntrappedLiquorSqueezing_tons_','ID_'});

    % Find all of the remaining fieldnames (TDS, LiquorPH, etc) and save
    % the field names into a cell array "fields". 
    fields = fieldnames(Temp); 
  
% Remove fields that will not be plotted
 fields([1,23,24,25,26,27,29,...
                30,31,34,35,36,38,39,...
                40,41,43,44,45,46,48,49,...
                50,51,53,54,55,56,58,59,...
                60,61,63,64,65,66,68,69,...
                70,71,73,74,75,76,78,79,...
                80,81,83]) = [];

     
    % Find all the data entries that have a value of "0" for the repeat.
    % This will always be the first data entry for a specific time point
    Rep0 = find(Temp.Repeat_ == 0);
    for i = 1:length(Rep0)
        % Find all the repeats associated with the current cooking time
        k = find(Fines.(field_names{l}).Time == Fines.(field_names{l}).Time(Rep0(i)));
        
        % Save the relevant data to the "Fines" structure.
        % See description for Chips for more info
        for j = 1:length(fields)
            Fines.(field_names{l}).Repeats.(fields{j}){i} = Temp.(fields{j})(k);
            try 
                Fines.(field_names{l}).Mean.(fields{j})(i) = mean(Temp.(fields{j})(k));
                Fines.(field_names{l}).STD.(fields{j})(i) = std(Temp.(fields{j})(k));
            catch

            end
        end
    end
    
    % Remove redunandant time points
    Fines.(field_names{l}).Time = unique(Fines.(field_names{l}).Time);
    
end

,

Answer 1

[Walter Roberson]

RawData = readtable('ExperimentalDatabaseWithoutEmptyCells.xlsx','Range','A1:CF88');

You read 84 columns (CF -> 84)

    Temp = removevars(Temp, {'Date', 'Run_', 'CookingTime_min_', ...
                             'CookingTemperature__C_', 'CookingPressure_bar_', ...
                             'WoodMass_g_', 'SteamMass_g_','ParticleSize', ...
                             'Na2SO3ODWBasis___','Na2CO3ODWBasis___', ...
                             'EntrappedLiquorSqueezing_tons_','ID_'});

You remove up to 12 of them. The result will have between 72 and 84 columns, depending how many of the variables were found

  fields([1,23,24,25,26,27,29,...
                30,31,34,35,36,38,39,...
                40,41,43,44,45,46,48,49,...
                50,51,53,54,55,56,58,59,...
                60,61,63,64,65,66,68,69,...
                70,71,73,74,75,76,78,79,...
                80,81,83]) = [];

You delete assuming that there are 83 or more field names... but the actual number of field names is going to be somewhere between 72 and 84.

You are assuming a fixed ordering of field names -- but if you are going to do that, then instead of using removevars(), assume the same fixed order, so that you can predict what the resulting field names will be. Or setdiff() the field names against a list of names you know you want to remove.

Mixing access by field name and access by field number is asking for trouble. Working by field name is more robust

Perhaps instead of removevars(), you sould make Temp by explicitly selecting the variables you want to keep, so that you will know how many their are and their order.

The actual result of removevars() is 75 variables remaining, by the way.

[Dursman Mchabe]

Thanks alot for a precise answer Walter.

I must quickly learn/try to explicitly select variables.

[Walter Roberson]

Temp = Temp(:,{'Time', 'PKa', 'MagicSmoke', 'Elote'});   %--> select explicit variables

[Dursman Mchabe]

Wow...so simple! Thanks Walter.

[Dursman Mchabe]

I have made Temp by explicitly selecting the variables I want to keep in this way:

    fields = Temp(:,{'TDS_mg_g_', 'LiquorPH', 'LiquorAceticAcid_g_L_', 'LiquorGlucose_g_L_',...
        'LiquorXylose_g_L_','SampleMass_mg_',	'UV_Absorbance', 'LiquorLignin_g_L_', 'InitialNa2SO3_g_L_',...
      'VolumeOfKIO3_mL__Titrated1', 'VolumeOfKIO3_mL__Titrated2',...
        'VolumeOfKIO3_mL__Titrated3',	'AverageVolumeOfKIO3_mL__Titrated',...
        'LiquorResidualNa2SO3_g_L_','PulpAshContent1_w_w__', 'PulpAshContent2_w_w__',...
        'PulpAshContent3_w_w__', 'AveragePulpAshContent_w_w__',...
        'H2OExtractives1_w_w__',	'H2OExtractives2_w_w__',	'H2OExtractives3_w_w__',...
        'AverageH2OExtractives_w_w__',	'EtOHExtractives1_w_w__',...
        'EtOHExtractives2_w_w__',	'EtOHExtractives3_w_w__',	'AverageEtOHExtract_w_w__',...
       'TotalExtractives1_w_w__',	'TotalExtractives2_w_w__',...
        'TotalExtractives3_w_w__',	'AverageTotalExtract_w_w__',...
        'AcidInsolubleLignin_ODW_1_', 'AcidInsolubleLignin_ODW_2_',	'AcidInsolubleLignin_ODW_3_',...
        'AverageAcidInsolubleLignin_ODW__',	'AcidSolubleLignin_ODW_1_',	'AcidSolubleLignin_ODW_2_',...
        'AcidSolubleLignin_ODW_3_',	'AverageAcidSolubleLignin_ODW__',		'TotalLignin1_w_w__',...
        'TotalLignin2_w_w__',	'TotalLignin3_w_w__',	'AverageTotalLignin___', 'TotalCellulose1___',...
        'TotalCellulose2___',	'TotalCellulose3___',	'AverageTotalCellulose___',	...
        'TotalHemicellulose1___',	'TotalHemicellulose2___',	'TotalHemicellulose3___',...
        'AverageTotalHemicellulose___',	'Xylose1___',	'Xylose2___',	'Xylose3___',...
        'AverageXylose___',		'Glucose1___',	'Glucose2___',	'Glucose3___',...
        'AverageGlucose___'}); 

However, it seems Matlab 'LENGTH' function does not allow for input arguments of type 'table'. When I try, to use:

     for j = 1:length(fields)
            Chips.(field_names{l}).Repeats.(fields{j}){i} = Temp.(fields{j})(k);
            try 
                Chips.(field_names{l}).Mean.(fields{j})(i) = mean(Temp.(fields{j})(k));
                Chips.(field_names{l}).STD.(fields{j})(i) = std(Temp.(fields{j})(k));
            catch

            end
        end

I get the following error message:

        Error using tabular/length (line 212)
Undefined function 'LENGTH' for input arguments of type 'table'.  Use the height, width, or size functions instead.

Error in ExperimentalDatabasePlotting (line 119)
        for j = 1:length(fields)

,

[Dursman Mchabe]

When use the number, like this:

for j = 1: 56% length(fields)
            Chips.(field_names{l}).Repeats.(fields{j}){i} = Temp.(fields{j})(k);
            try 
                Chips.(field_names{l}).Mean.(fields{j})(i) = mean(Temp.(fields{j})(k));
                Chips.(field_names{l}).STD.(fields{j})(i) = std(Temp.(fields{j})(k));
            catch

            end
        end

I get the following error message:

        Error using ExperimentalDatabasePlotting (line 120)
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,:).

,

[Walter Roberson]

When you index into Temp assign the results to Temp. Then

fields = Temp.Properties.VariableNames;

That is fields is names in your code.

[Dursman Mchabe]

I am a bit lost now... what would be Properties example in this case? Sorry for a stupid question.

[Dursman Mchabe]

Are you reffering to the similar way I have stored constant parameters under Description?, e.g.:

 Chips.(field_names{l}).Description = struct(  'T', Temp.CookingTemperature__C_(1), ...
                                                  'P', Temp.CookingPressure_bar_(1), ...
                                                  'WoodMass', Temp.WoodMass_g_(1), ...
                                                  'SteamMass', Temp.SteamMass_g_(1), ...
                                                  'Na2SO3ODWBasis', Temp.Na2SO3ODWBasis___(1), ...
                                                  'Na2CO3ODWBasis', Temp.Na2CO3ODWBasis___(1),...
                                                  'LiquidToWoodRatio',Temp.LiquidToWoodRatio(1),...
                                                  'InitialNa2SO3_g_L_',Temp.InitialNa2SO3_g_L_(1));

,