On Thu, 25 Sep 2008, Mark Na wrote:

Hello,

I have a dataframe with 9 columns, and I would like to sort (order) the right-most eight of them alphabetiaclly, i.e.:

ID1 ID2 F G A B C E D

would become

ID1 ID2 A B C D E F G

Right now, I'm using this code:

attach(data)
data<-data.frame(ID1,ID2,data[,sort(colnames(data)[3:9])])
detach(data)

but that's not very elegant. Ideally I could specify which columns to sort and which to leave "as is" (but my attempts to do so have failed).

Thank you,

Mark


OK, my first response was a bit quick and ignored the need to keep the first two columns.

The major point is that you can avoid the attach/detach if you use names in the subsetting:

df <- data.frame(k1=1:2,k2=3:4,z=5:6,a=7:8,y=9:10)
df
  k1 k2 z a  y
1  1  3 5 7  9
2  2  4 6 8 10
sortdf <- df[,c(names(df)[1:2],sort(names(df)[3:5]))]
sortdf
  k1 k2 a  y z
1  1  3 7  9 5
2  2  4 8 10 6

The rearrangement of the columns is just a one-liner and (in my view at least) easy to read and understand

David Scott

_________________________________________________________________
David Scott     Department of Statistics, Tamaki Campus
                The University of Auckland, PB 92019
                Auckland 1142,    NEW ZEALAND
Phone: +64 9 373 7599 ext 86830         Fax: +64 9 373 7000
Email:  [EMAIL PROTECTED]

Graduate Officer, Department of Statistics
Director of Consulting, Department of Statistics

______________________________________________
[email protected] 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.

Reply via email to