[R] Simple question on finding duplicates
arun
smartpink111 at yahoo.com
Wed Jul 25 22:26:48 CEST 2012
HI,
Try this:
a <- data.frame( col1 = c(1,2,3,3,4))
a<-within(a, duplicate<-c(0,ifelse(diff(a$col1)==0,1,0)))
a
col1 duplicate
1 1 0
2 2 0
3 3 0
4 3 1
5 4 0
A.K.
----- Original Message -----
From: Jeff <r at jp.pair.com>
To: r-help at r-project.org
Cc:
Sent: Wednesday, July 25, 2012 4:05 PM
Subject: [R] Simple question on finding duplicates
I'm trying to find duplicate values in a column of a data frame. For
example, dataframe (a) below has two 3's. I would like to mark each value of
each row as either not being a duplicate of the one before (0), or as a
duplicate (1) - for example, as in dataframe (b). In SPSS, I would simply
compare each value to it's "lagged" value, but I can't figure out how to do
this with R.
Can someone point me in the right direction?
Thanks
a <- data.frame( col1 = c(1,2,3,3,4))
b <- data.frame( col1 = c(1,2,3,3,4), duplicate = c(0,0,0,1,0))
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