Creating a three column table from matrix

If I have a matrix, how can I make a table with three columns that are row number, column number, and then the value for that row-column? And then, add a 4th column with the row-column number? example in picture

Answer 1

[Julian Hapke]

Hi,

because you want a string in your 4th column, you need a cell array. here's my q&d solution:

A=rand(3,3);
new = cell(numel(A),4);
kk=1;
for ii = 1:size(A,1);
  for jj = 1:size(A,2);
  new{kk,1}=ii;
  new{kk,2}=jj;
  new{kk,3}=A(ii,jj);
  new{kk,4}=[num2str(ii) '-' num2str(jj)];
  kk=kk+1;
  end;
end

Regards

Julian

[Colby]

Thank you very much for your help!!!

[Image Analyst]

Note: this solution does not give a table like you asked for, and like the two other solutions give. Tables are a useful new data type introduced in release R2013b.

Answer 2

[Image Analyst]

Try this:

row = [1;1;1;2;2;2;3;3;3]
column = repmat([1:3]', [3, 1])
value = [1;2;3;6;7;8;11;12;13]
table1 = table(row, column, value)

% Now make a second table with an additional column of strings.
for k = 1 : length(row)
  rMinusc{k} = sprintf('%d - %d', row(k), column(k));
end
rMinusc = rMinusc'; % Transpose
table2 = table(row, column, value, rMinusc)

In the command window:

table2 = 
    row    column    value    rMinusc
    ___    ______    _____    _______
    1      1           1      '1 - 1'
    1      2           2      '1 - 2'
    1      3           3      '1 - 3'
    2      1           6      '2 - 1'
    2      2           7      '2 - 2'
    2      3           8      '2 - 3'
    3      1          11      '3 - 1'
    3      2          12      '3 - 2'
    3      3          13      '3 - 3'

[Colby]

Thanks a lot for your help!!!

Answer 3

[Jorge]

Should be something like this. Didn't run it, though... The table you seek is in columns. Use table() to arrange.

    [n,m]=size(matrix);
    counter=0;
      for i=1:n
       for j=1:m
        counter=counter+1;
        rows(counter)=i;
        columns(counter)=j;
        values(counter)=matrix(i,j);
        rc{counter}=strcat(i,'-',j)
       end
      end
    table=[rows columns values rc];

[Colby]

Thanks a lot for the help!!!