how do I remove rows with duplicated values?

Question

jesus escareno 2017-3-7

评论： Otto Liljansalo 2024-3-14

let say i have matrix A

 A = [1 2 3 4 5;
       3 5 7 9 11;
       1 1 4 5 7;
       3 5 6 6 9;
       1 4 10 15 16]

and wanted to remove all rows with values that repeated with each other. Then A will become

 A = [1 2 3 4 5;
       3 5 7 9 11;
       1 4 10 15 16]

Thanks for the help in Advance

Answer 1

the cyclist 2017-3-7

编辑：the cyclist 2017-3-7

Here is a one-liner:

A(any(diff(sort(A,2),[],2)==0,2),:)=[];

If you are certain that each row is already in numerical order (as in your example), you can skip the sorting step.

The algorithm is the following:

Use sort to sort the values in each row
Use diff to get the difference between consecutive values in each row
Use any to check if any of those differences equal zero (indicating a duplicate values)
Use the output of the any command, which is a logical index, to delete the rows that have duplicates

Works perfectly. Thank you

Otto Liljansalo 2024-3-14

Nice programming there!