Stefan:
Use the droplevels function...
dat <- read.table(textConnection("
treat yield
1 cont 98.7
2 cont 97.2
3 cont 96.1
4 cont 98.1
5 10 103.0
6 10 101.3
7 10 102.1
8 10 101.9
9 30 121.1
10 30 123.1
11 30 119.7
12 30 118.9
13 60 109.9
14 60 110.1
15 60 113.1
16 60 112.3"),header=T)
dat
plot(dat$treat,dat$yield)
dat.sub <- subset(dat,treat!="cont");dat.sub
dat.sub <- droplevels(dat.sub) # drop unwanted levels
plot(dat.sub$treat,dat.sub$yield)
Felipe D. Carrillo
Supervisory Fishery Biologist
Department of the Interior
US Fish & Wildlife Service
California, USA
http://www.fws.gov/redbluff/rbdd_jsmp.aspx
From: "Schreiber, Stefan" <stefan.schrei...@ales.ualberta.ca>
>To: r-help@r-project.org
>Sent: Tuesday, November 1, 2011 2:28 PM
>Subject: [R] factor level issue after subsetting
>
>Dear list,
>
>I cannot figure out why, after sub-setting my data, that particular item
>which I don't want to plot is still in the newly created subset (please
>see example below). R somehow remembers what was in the original data
>set. A work around is exporting and importing the new subset. Then it's
>all fine; but I don't like this idea and was wondering what am I missing
>here?
>
>Thanks!
>Stefan
>
>P.S. I am using R 2.13.2 for Mac.
>
>> dat<-read.csv("~/MyFiles/data.csv")
>> class(dat$treat)
>[1] "factor"
>> dat
> treat yield
>1 cont 98.7
>2 cont 97.2
>3 cont 96.1
>4 cont 98.1
>5 10 103.0
>6 10 101.3
>7 10 102.1
>8 10 101.9
>9 30 121.1
>10 30 123.1
>11 30 119.7
>12 30 118.9
>13 60 109.9
>14 60 110.1
>15 60 113.1
>16 60 112.3
>> plot(dat$treat,dat$yield)
>> dat.sub<-dat[which(dat$treat!='cont')]
>> class(dat.sub$treat)
>[1] "factor"
>> dat.sub
> treat yield
>5 10 103.0
>6 10 101.3
>7 10 102.1
>8 10 101.9
>9 30 121.1
>10 30 123.1
>11 30 119.7
>12 30 118.9
>13 60 109.9
>14 60 110.1
>15 60 113.1
>16 60 112.3
>> plot(dat.sub$treat,dat.sub$yield)
>
> [[alternative HTML version deleted]]
>
>______________________________________________
>R-help@r-project.org mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.
>
>
>
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
