How a table columns are named using MATALB

I have a fetaure table with 5*10 size.Now I woul like to name each of the Coloumns

I would like to name ecah coloumn and also again 5 coloumn need to give name with Title1 as shown below.Please help me using MATLAB

[Stephen23]

Adding "headers" (i.e. column/variable names) is easy if you convert the data to a table: https://www.mathworks.com/help/matlab/ref/array2table.html

However a heirarchy of column/variable names like you show is not possible in one table :https://www.mathworks.com/matlabcentral/answers/541568-nested-tables-with-duplicate-sub-column-names

You could create nested tables, but that does complicate accessing and processing your data.

Answer 1

[Simon Chan]

Something like the following may be similar to what you want.

clear; clc;
combine_vector = randi(10,5,10);
Title1 = array2table(combine_vector(:,1:5),'VariableNames',compose('feature%d',1:5));
Title2 = array2table(combine_vector(:,6:10),'VariableNames',compose('Sfeature%d',1:5));
T = table(Title1,Title2)

T = 5×2 table
                             Title1                                                        Title2                            
    feature1    feature2    feature3    feature4    feature5    Sfeature1    Sfeature2    Sfeature3    Sfeature4    Sfeature5
    ________________________________________________________    _____________________________________________________________

       1            9          10          6            3           5            2            9            2            4    
       3           10           4          8           10           4           10           10            4            4    
       2            6           1          8            7           4            7            5            8            5    
       6            2           2          8            7           2            6            8            6            2    
       6            6          10          2            9           2            4            8            2            8    

[C PRASAD]

Thanks for the response.If tha table is of Size 28*75. If we want to Write first 5 columns are Enrgy1,variance1,Standard Deviation1,Waveform length1,Entrophy1 and next 5 feature with Energy2 so on for 75 coloums and again each 5 coumns needd to be named as H1 to H15.How does we implement using MATLAB.

[Simon Chan]

Please refer to the following:

As mentioned by Stephen, it becomes a little bit complicated.

clear; clc;
Nz = 15;
combine_vector = randi(10,28,75);                                                   % Simulate data
TopTitle = compose('H%d_Features',1:Nz);                                            % Prepare the top title
SubTitle = ["Energy","Variance","Standard_Deviation","Waveform_Length","Entrophy"]; % Prepare the sub title
%
T = cell(1,Nz);                                                                     
for k = 1:Nz
    Ttemp = array2table(combine_vector(:,5*(k-1)+1:5*(k-1)+5),'VariableNames',strcat(SubTitle,num2str(k)));
    T{k} = table(Ttemp,'VariableName',TopTitle(k));
end
Tcombine = cat(2,T{:});
Tcombine(:,1:3)                         % Table is too big and just display the first 3 columns

ans = 28×3 table
                                    H1_Features                                                                     H2_Features                                                                     H3_Features                                 
    Energy1    Variance1    Standard_Deviation1    Waveform_Length1    Entrophy1    Energy2    Variance2    Standard_Deviation2    Waveform_Length2    Entrophy2    Energy3    Variance3    Standard_Deviation3    Waveform_Length3    Entrophy3
    ____________________________________________________________________________    ____________________________________________________________________________    ____________________________________________________________________________

       1           2                 1                     8               4           8           6                 7                     3              10           4           8                 9                     8               2    
       7           9                 5                    10               4          10           9                10                    10               9           8           5                10                     8               7    
       5           4                10                     6               5           7           2                 1                     4               8           9           4                 8                     5              10    
       9           6                 9                     4               1           9           2                 4                     3              10           6           4                 4                     9              10    
       8           9                 5                     7               3           8           7                 8                     9               5           4           6                 4                     6               3    
       5           4                 3                     2               4           5           4                 4                    10               9           5           7                10                     8               6    
       3           8                10                     8               8           6           7                 9                     4               4           8           3                 9                     5               9    
       8           1                10                     8               9           4           3                10                     7               8           3           5                 2                     3               6    
       5           5                 4                     5               2           9           7                 9                     1               7           2          10                10                     4               4    
       6           3                 4                     1               4           3           2                 8                     3               6           3           5                 4                     5               1    
       1           1                 4                     8               4           2           2                 4                     2               9           5           9                 8                     4               9    
       5           6                 8                     6               4           1           5                 5                     9               6           1           2                 5                     3               5    
       7           1                 4                     7               6           1           7                 3                     7               2           9           5                 6                    10               5    
       3           3                 2                     9               7           9           7                10                     6               1           4           1                 3                     8               5    
      10           3                 2                     4               3          10           8                 9                     7               9           4           1                 5                     7               9    
       8           1                 3                     1               5           6           9                 3                     4               7           1           1                10                     3               3    

[C PRASAD]

I'm so glad for your response sir.But if I run this code in matlab2018a, I got error at

"Ttemp = array2table(combine_vector(:,5*(k-1)+1:5*(k-1)+5),'VariableNames',strcat(SubTitle,num2str(k)));"

The Error is

Plese help me with this.Iam so thankful to you sir

[Simon Chan]

Could you please upload your code regarding varaibles 'TopTitle' and 'SubTitle'.

[Stephen23]

Rather than putting everything into one line, simply define all of the input arguments as variables:

arr = combine_vector(..);
vnm = strcat(..);
Ttemp = array2table(arr,'VariableName',vnm)

Not only will you have neater and clearer code, but you can then easily check the input arguments yourself: you will find that variable names are not a cell array of character vectors, just as the error message states.

[C PRASAD]

Thank you so much sir.If I wolud like to save all titles first columns to one variable and all second coloumns to another variable and so on.

A=Title1.features1(:,1)

B=Title1.Sfeatures2(:,2)

I can use these but if I have a 12*15 size and I wolud like to save 1,6,11 coumns data to one variable and 2,7,12 to another variable ,3,8,13 and 4,9,14 and 5,10,15 to another variable using any loop.Please help me with this sir

clc

clear all

close all

X=randi(10,12,75);

Nz = 15;

TopTitle = compose('H%d_Features',1:Nz); % Prepare the top title

T = cell(1,Nz);

for k = 1:Nz

arr=X(:,5*(k-1)+1:5*(k-1)+5);

vnm =strcat({'Energy','variance','std','wl','entrophy'},num2str(k));

Ttemp = array2table(arr,'VariableNames',vnm);

T{k} = table(Ttemp,'VariableName',TopTitle(k));

end

Tcombine = cat(2,T {:});

Prasad=Tcombine(:,1:Nz);

%% Channel1 features %%

s11=Prasad.H1_Features(:,1);

s12=Prasad.H2_Features(:,1);

s13=Prasad.H3_Features(:,1);

s14=Prasad.H4_Features(:,1);

s15=Prasad.H5_Features(:,1);

%% Channel2 Features %%

s21=Prasad.H1_Features(:,2);

s22=Prasad.H2_Features(:,2);

s23=Prasad.H3_Features(:,2);

s24=Prasad.H4_Features(:,2);

s25=Prasad.H5_Features(:,2);

%% Channnel3 Features %%

s31=Prasad.H1_Features(:,3);

s32=Prasad.H2_Features(:,3);

s33=Prasad.H3_Features(:,3);

s34=Prasad.H4_Features(:,3);

s35=Prasad.H5_Features(:,3);

%% Channel4 Features %%

s41=Prasad.H1_Features(:,4);

s42=Prasad.H2_Features(:,4);

s43=Prasad.H3_Features(:,4);

s44=Prasad.H4_Features(:,4);

s45=Prasad.H5_Features(:,4);

%% Channel5 Features %%

s51=Prasad.H1_Features(:,5);

s52=Prasad.H2_Features(:,5);

s53=Prasad.H3_Features(:,5);

s54=Prasad.H4_Features(:,5);

s55=Prasad.H5_Features(:,5);

I want to use a loop to save channel 1 feature into one variable and like wise all the featutres sir.Please help me with the help of any loop function

[Stephen23]

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

[Simon Chan]

There is no need to save them in different variables. Stephen's recommendation is absolutely right.

In case you would like to use data on column 1,6,11. You can directly retrieve them from the variable combine_vector as follows:

combine_vector = randi(10,28,75);  
combine_vector(:,[1 6 11])

ans = 28×3

8 4 10 9 6 10 1 7 1 9 7 4 8 3 2 5 2 6 8 3 10 3 8 4 10 10 10 4 3 8