Hi,
Try this:
dat <- read.table(text="
ParticipID??? ERP? Electrode
1??????? s1? 0.0370????? FP1
2??????? s2 35.0654????? FP2
3??????? s3 -3.3852??????? F4
4??????? s4? 2.6119??????? P3
5??????? s5? 0.1224??????? P4
6??????? s6 -5.3153??????? O1
7??????? s7 -3.88????????? F4
8??????? s8? -4.988??????? FP1?
", header=TRUE)
str(d)
tomatch <- c("FP1", "FP2", "F4")
#You can use either one of these
dat[with(dat,Electrode%in%tomatch),]
dat[dat$Electrode%in%tomatch,]
#or
dat2<-within(dat,{Electrode=Electrode%in%tomatch})
dat[dat2$Electrode==TRUE,]
#? ParticipID???? ERP Electrode
#1???????? s1? 0.0370?????? FP1
#2???????? s2 35.0654?????? FP2
#3???????? s3 -3.3852??????? F4
#7???????? s7 -3.8800??????? F4
#8???????? s8 -4.9880?????? FP1
A.K.
----- Original Message -----
From: simona mancini <mancinisimona at yahoo.it>
To: "r-help at r-project.org" <r-help at r-project.org>
Cc:
Sent: Friday, August 10, 2012 5:07 AM
Subject: [R] subsetting levels of a vector
Hi,
I need to subset different levels of vector in a dataset to create a new dataframe that contains only these. These observations are not numerical, so I can't use the subset() function (at least this is the response I get from R).
Suppose the dataframe looks like this:
? ParticipID??? ERP?? Electrode
1???????? s1? 0.0370?????? FP1
2???????? s2 35.0654?????? FP2
3???????? s3 -3.3852??????? F4
4???????? s4? 2.6119??????? P3
5???????? s5? 0.1224??????? P4
6???????? s6 -5.3153??????? O1
I want to create a subset of the dataframe with only the FP1, FP2, F4 levels of Electrode, how do I do?
(actually the levels I have to filter are much more than these three, but this is just to give an example).
I know this is a trivial question, but I am still getting familiar with R...
Thanks a lot,
s.
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