On Thu, 19 Jun 2014 02:50:20 PM Chris Dolanc wrote:
> Hello,
>
> I have a data frame with > 5000 columns and I'd like to be able to
make
> subsets of that data frame made up of certain columns by using
part of
> the column names. I've had a surprisingly hard time finding
something
> that works by searching online.
>
> For example, lets say I have a data frame (df) of 2 obs. of 6
variables.
> The 6 variables are called "1940_tmax", "1940_ppt", "1940_tmin",
> "1941_tmax", "1941_ppt", "1941_tmin". I want to create a new data
frame
> with only the variables that have "ppt" in the variable (column)
name,
> so that it looks like this:
>
> plot name 1940_ppt 1941_ppt
> 774-CL 231 344
> 778-RW 228 313
>
Hi Chris,
One way is to get the column indices:
grep("ppt",names(df))
[1] 2 5
so,
newdf<-df[grep("ppt",names(df))]
and then you apparently want to add a column with some other
information, so probably:
newdf<-cbind(<something_else>,
df[grep("ppt",names(df))])
Jim
______________________________________________
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.
