MATLAB: How to give unique id to similar row

raw id

hi I would like to add third column to the array represents unique id for a similar rows in the array I will be grateful for any help and thank you in advance
#     30    10
#     30   191
#     30    10
#     45   206
#     30   191
#     45   206
#     45   206
#    155   206
#    155   206
#    170   191
#    155   206
#    170    11
#    170   191
#    170    11

Best Answer

I am not certain what result you want.
The unique function might be an option:
A = [30    10
     30   191
     30    10
     45   206
     30   191
     45   206
     45   206
    155   206
    155   206
    170   191
    155   206
    170    11
    170   191
    170    11];
[Au,~,ID] = unique(A, 'rows','stable');
Out = [A ID]
Out =
    30    10     1
    30   191     2
    30    10     1
    45   206     3
    30   191     2
    45   206     3
    45   206     3
   155   206     4
   155   206     4
   170   191     5
   155   206     4
   170    11     6
   170   191     5
   170    11     6
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