How can I strip duplicates?

I wish to remove all duplicate rows based off of the first column. That is, I want to just strip the excess away. I am struggling to understand how to implement "unique" here. Thanks in advance

5 Comments

Looks like you probably just want the 'rows' optional parameter...
res=unique(data,'rows'); % keep original, too, or
data=unique(data,'rows'); % throw the original duplicates away
Perhaps something got lost as you transferred your answer here, but it looks like both lines of code will produce the same output.
Yes, but as the comments note the second overwrites the data array whereas the first creates a new result variable, keeping the original data as well in case there is some other reason to have it, too, going forward.
Ah, got it. Thanks.
per isakson
per isakson on 13 Oct 2021
Edited: per isakson on 13 Oct 2021
The values in the first column are not whole numbers. Thus uniquetol is appropriate.

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Answers (1)

If you want
  1. remove duplicates only based on values in the first column
  2. Do not want the returned values be sorted
then you need to do this
in=[[5;5;5;4;4;4;3;3;3;1],(1:10)'];
[~, index]=unique(in(:,1),'stable');
out=in(index,:)

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R2020b

Asked:

on 8 Apr 2021

Edited:

on 13 Oct 2021

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