adding index to matrix rows

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Ali
Ali on 27 May 2016
Commented: Allison Chua on 6 Oct 2020
I have a matrix like this
1 0
0 2
2 1
0 3
3 2
2 0
4 1
1 6
6 4
6 1
I would like to have the following matrix, please help me if you have the answer.
0: 1 0
1: 0 2
2: 2 1
3: 0 3
4: 3 2
5: 2 0
6: 4 1
7: 1 6
8: 6 4
9: 6 1

Accepted Answer

Guillaume
Guillaume on 27 May 2016
Edited: Stephen23 on 27 May 2016
Please use the code format button {}Code rather than putting spaces between each line.
A matrix can only contain numbers, colons are not allowed. If it's only for display that you want that, there's no simple way to force matlab to display matrices like this.
Possibly, you can convert the matrix into a table and assign names to the rows:
m = [1 0;0 2; 2 1; 0 3; 3 2; 2 0; 4 1];
t = array2table(m, 'RowNames', sprintfc('%d:', 1:size(m, 1)), 'VariableNames', sprintfc('col%d', 1:size(m, 2)))
Otherwise, you'll have to write your own display function which is far from trivial if you want it to play nicely with format.
  6 Comments
Guillaume
Guillaume on 27 May 2016
Well simply modify the relevant fprintf:
fprintf('%d:', row - 1);
Ali
Ali on 27 May 2016
Many thanks Guillaume. you helped me a lot

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More Answers (1)

Renato Agurto
Renato Agurto on 27 May 2016
Edited: Renato Agurto on 27 May 2016
Is this what you want? Or what do you mean with ':' in a matrix?
A = [1 0;
0 2;
2 1;
0 3;
3 2;
2 0;
4 1;
1 6;
6 4;
6 1];
B = [(0:size(A,1)-1)' A];
  2 Comments
Ali
Ali on 27 May 2016
Many thanks for the response. It is appreciated. I have a matrix with 500 row and 2 columns. I would like to be converted in this format: for instance, this is part of the results that I am looking for
0: 1 0
1: 0 2
2: 2 1
3: 0 3
4: 3 2
5: 2 0
6: 4 1
Allison Chua
Allison Chua on 6 Oct 2020
@Renato Agurto - thank you SO much!!! I'm so terrible at Matlab syntax, and this was exactly what I needed.

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