[R] concatenating range of columns in dataframe
ulrik.stervbo at gmail.com
Fri Mar 10 08:24:31 CET 2017
the unite function of the tidyr package achieves the same as Jim suggested,
but in perhaps a slightly more readable manner.
On Fri, 10 Mar 2017 at 07:50 Jim Lemon <drjimlemon at gmail.com> wrote:
> Hi Evan,
> How about this:
> On Fri, Mar 10, 2017 at 3:16 PM, Evan Cooch <evan.cooch at gmail.com> wrote:
> > Suppose I have the following data frame (call it df):
> > Trt y1 y2 y3 y4
> > A1A 1 0 0 1
> > A1B 1 1 0 0
> > A1 C 0 1 0 1
> > A1D 1 1 1 1
> > What I want to do is concatenate columns y1 -> y4 into a contiguous
> > (which I'll call df$conc), so that the final df looks like
> > Trt Conc
> > A1A 1001
> > A1B 1100
> > A1C 0101
> > A1D 1111
> > Now, if my initial dataframe was simply
> > 1 0 0 1
> > 1 1 0 0
> > 0 1 0 1
> > 1 1 1 1
> > then apply(df,1,paste,collapse="") does the trick, more or less.
> > But once I have a Trt column, this approach yields
> > A1A1001
> > A1B1100
> > A1C0101
> > A1D1111
> > I need to maintain the space between Trt, and the other columns. So, I'm
> > trying to concatenate a subset of columns in the data frame, but I don't
> > want to have to do something like create a cahracter vector of the column
> > names to do it (e.g., c("y1","y2","y3","y4"). Doing a few by hand that
> > is easy, but not if you have dozens to hundreds of columns to work with.
> > Ideally, I'd like to be able to say
> > "concatenate df[,2:4], get rid of the spaces, pipe the concatenated
> > to a new named column, and drop the original columns from the final df.
> > Heuristically,
> > df$conc <- concatenate df[,2:4] # making a new, 5th column in df
> > df[,2:4] <- NULL # to drop original columns 2 -> 4
> > Suggestions/pointers to the obvious appreciated.
> > Thanks in advance!
> > ______________________________________________
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> > and provide commented, minimal, self-contained, reproducible code.
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> PLEASE do read the posting guide
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