try the following:
dat - data.frame(
id = gl(10, 5),
y = rnorm(50),
time = rep(1:5, 10),
sex = gl(2, 25, labels = c(male, female)),
age = round(rep(runif(10, 18, 55), each = 5), 1)
)
dat[tapply(row.names(dat), dat$id, head, n = 1), ]
dat[!duplicated(dat$id), ]
I hope it helps.
Best,
Dimitris
Dimitris Rizopoulos
Biostatistical Centre
School of Public Health
Catholic University of Leuven
Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
http://www.student.kuleuven.be/~m0390867/dimitris.htm
- Original Message -
From: Bob Green [EMAIL PROTECTED]
To: r-help@r-project.org
Sent: Tuesday, April 01, 2008 11:37 AM
Subject: [R] filtering out duplicates creating a dataframe with
unique id
Hello,
I am working on a dataframe that contains a number of duplicates
(e.g
a person may have more than one court appearance). There are 539
rows. If I run the code:
length(unique(Feb25$ Patient.Id))
this indicates there are 508 unique individuals. I have been unable
to work out how to filter out rows where there is a duplicate id so
that the resulting dataframe consists only of the one id per person,
and this id, is the first one thartappears.
I was also interested in creating a data frame that consisted of
these removed duplicates.
Any assistance with the code to do this is much appreciated,
regards
Bob Green
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and provide commented, minimal, self-contained, reproducible code.
