[R] Unique subsetting question

[Ista Zahn]

Hi Andrew,
You can use duplicated() to index the rows you wish to keep, like this:


test.dat <- data.frame(a=c(1,1:5,5:10), b=1:12, c=letters[1:12]) #make up data

duplicated(test.dat$a) # see what duplicated() function does
!duplicated(test.dat$a) # see how we can invert using the ! function
so that we get non-duplicated

test.dat[!duplicated(test.dat$a),] # this is the important bit: use
indexing to select non-duplicated rows.


Best,
Ista

On Wed, Sep 22, 2010 at 12:35 PM, AndrewPage <savejarvis at yahoo.com> wrote:
>
> I understand how duplicated and unique work for a list where all parts of a
> given row are duplicated, or how to find duplicated values if I'm just
> looking at that first column, but in this case  the rows for 1954 and 1955
> are not completely the same; only quarter 1 is duplicated, so I'm not sure
> how to apply either duplicated or unique in that case.
>
> Thanks,
> Andrew
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-- 
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org