[R] concatenating range of columns in dataframe

[Ulrik Stervbo]

Hi Evan,

the unite function of the tidyr package achieves the same as Jim suggested,
but in perhaps a slightly more readable manner.

Ulrik

On Fri, 10 Mar 2017 at 07:50 Jim Lemon <drjimlemon at gmail.com> wrote:

> Hi Evan,
> How about this:
>
> df2<-data.frame(Trt=df[,1],Conc=apply(df[,2:5],1,paste,sep="",collapse=""))
>
> Jim
>
> 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
> string
> > (which I'll call df$conc), so that the final df looks like
> >
> > Trt      Conc
> > A1A   1001
> > A1B   1100
> > A1C  0101
> > A1D   1111
> >
> >
> > Now, if my initial dataframe was simply
> >
> >  1   0  0  1
> >  1   1  0  0
> >   0  1  0  1
> >   1  1  1  1
> >
> > then apply(df,1,paste,collapse="") does the trick, more or less.
> >
> > But once I have a Trt column, this approach yields
> >
> > A1A1001
> > A1B1100
> > A1C0101
> > A1D1111
> >
> > I need to maintain the space between Trt, and the other columns. So, I'm
> > trying to concatenate a subset of columns in the data frame, but I don't
> > want to have to do something like create a cahracter vector of the column
> > names to do it (e.g., c("y1","y2","y3","y4"). Doing a few by hand that
> way
> > is easy, but not if you  have dozens to hundreds of columns to work with.
> >
> >  Ideally, I'd like to be able to say
> >
> > "concatenate df[,2:4], get rid of the spaces, pipe the concatenated
> columns
> > to a new named column, and drop the original columns from the final df.
> >
> > Heuristically,
> >
> > df$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!
> >
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
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> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>

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