I would like to get an example of the difference between the maximum and minimum values by grouping grpstats or looping statements

Hello! I have a large Matlab dataset, the dataset formats are as following example:

id1 id2 value

148 168 80

148 168 82

148 168 96

568 566 66

568 566 28

568 566 88

568 566 62

166 688 88

166 688 82

......

Now I want each set of the same (id1,id2) will get a corresponding difference between the maximum value and the minimum value, for example:

id1 id2 diff

148 168 16

568 566 60

166 688 6

......

How can I get the results like this by using grpstats or looping statements？ Thanks!

Answer 1

[Jos (10584)]

Let M be your N-by-3 table, with columns [id1 id2 value] :

[out, ~, gi] = unique(M(:,[1 2]), 'rows')
out(:,3) = grpstats(M(:,3), gi, 'range')

[zheng linglin]

Your method works well！Thank you very much!