I am having trouble using unique and histc commands for the following task, anyone knows how the solve it?

A =

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

First column refers to the values and the second one refers to the occurances. How it is possible to convert this matrix to the following

A =

     1     5
     2     16
     3     5
     4     4
     5     18    
     6     2

thanks in advance

Answer 1

[Guillaume]

The command you need for this is |accumarray in it is simplest form:

Anew = [(1:max(A:, 1)' accumarray(A(:, 1), A(:, 2))]