All sorted
Thanks very much for your help Peter and Jannis.
Toni
Peter Alspach wrote:
Tena koe Toni
Assume your data is in a data.frame called toniData (naming a data.frame data
is not a good idea as data is a function in R - see ?data), and that Group is
of class character (try str(toniData)) then:
toniData[toniData$Group %in% 'A','Group'] <- 'C'
will work. But from your message below I suspect Group is of class factor. So
you either need to change its class:
toniData$Group <- as.character(toniData$Group)
or rename the level names. For example:
set.seed(0)
toniG <- factor(LETTERS[sample(1:2, size=10, replace=TRUE)])
toniG
[1] B A A B B A B B B B
Levels: A B
levels(toniG)
[1] "A" "B"
levels(toniG) <- c('C','B')
toniG
[1] B C C B B C B B B B
Levels: C B
Regarding your second question, see sub() (or gsub()) - again paying attention
to whether or not you are dealing with factor or character variables.
HTH ....
Peter Alspach
-----Original Message-----
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-
project.org] On Behalf Of Toni Pitcher
Sent: Friday, 23 July 2010 9:44 a.m.
To: r-help@r-project.org
Subject: [R] Changing some values within a variable
Hi
I'm new to R and would like some help with a couple of problems. I
suspect the solutions are quite simple.
I have a data.frame (data) with 40 variables and 5238 observations
created from ~150 text files using read.table.
I would like to change some of the entries within two different
columns.
Firstly, in the Group column I have groups A and B, I would like to
select all As and change to C. I have tried the following;
data$Group = ifelse(data$Group == 'A', "C", data$Group)
data$Group <- as.factor(data$Group)
This works to some extent, all As have been changes to Cs, but the Bs
have also been changed, in this case to "2", instead of remaining as
their original values. How do I get the Bs to stay the same?
Second problems is similar;
I need to change some of the Subject IDs. The required format is 3
numbers followed by 3 letters (999LLL). Some of the IDs have format
999LLL-LL, Thus I need to delete the -LL from the IDs.
How do I generically specify "find 999LLL-LL and replace with 999LLL"?
Many thanks in advance
Toni
--
Toni Pitcher PhD
Dept. of Medicine
University of Otago, Christchurch
Van der Veer Institute for Parkinson's and Brain Research
66 Stewart St
Christchurch 8011
New Zealand
Phone: +64 3 378 6075 (internal extn 86075)
Email: toni.pitc...@otago.ac.nz
______________________________________________
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.
--
Toni Pitcher PhD
Dept. of Medicine
University of Otago, Christchurch
Van der Veer Institute for Parkinson's and Brain Research
66 Stewart St
Christchurch 8011
New Zealand
Phone: +64 3 378 6075 (internal extn 86075)
Email: toni.pitc...@otago.ac.nz
______________________________________________
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.
