Hello,

thank you for your reply.

Actually, the whole rows would have to be averaged anyways - my mistake :-)
Besides the first column "name" there is one other string (chr) variable
"Test" in the dataset (the rows I want to average have always the same
Testvariable), the other variables are numeric or integer.

Best,

Verena


On Wed, May 28, 2014 at 2:57 PM, PIKAL Petr <petr.pikal@precheza.cz> wrote:

> Hi
>
> AFAIK you can not average values only in 2 columns leaving others intact.
> The exact code depends on what are in columns 2-39 in your data frame. If
> numbers, you can averege them as well.
>
> Something like
>
> dat.ag <- aggregate(dat[,-1], list(dat$Name), mean, na.rm=TRUE)
>
> if your data frame is named dat and first column calls Name. You get new
> object with aggregated values for the same Name.
>
> If some columns are nonnumeric the problem gets trickier and solution
> strongly depends what mode are those columns and what you want to do with
> them when aggregating values in column 40 and 41.
>
> Show us at least structure of your data frame.
>
> ?str
>
> Regards
> Petr
>
> > -----Original Message-----
> > From: r-help-bounces@r-project.org [mailto:r-help-bounces@r-
> > project.org] On Behalf Of Verena Weinbir
> > Sent: Wednesday, May 28, 2014 2:00 PM
> > To: arun
> > Cc: r-help
> > Subject: Re: [R] Dataframe: Average cells of two rows and replace them
> > with one row
> >
> > Hey guys,
> >
> > thank you very much for your help.  Since I am a R-newbie I am still
> > checking out how your code works and how I could adapt it to my
> > dataframe,
> > which has 124 rows and 41 columns/variables.  The first column would be
> > "name", the last ones, 40 and 41, contain the cells I want to average
> > for
> > some rows. Is it possible to read the dataframe without copying the
> > whole
> > thing into the text"" function (just tried it and got an error
> > message)?
> >
> > Thank you!
> >
> > Verena
> >
> >
> > On Wed, May 28, 2014 at 3:48 AM, arun <smartpink111@yahoo.com> wrote:
> >
> > > Hi,
> > > You can also try:
> > > dat <- read.table(text="Name C1 C2 C3
> > >   1  A  3  3  5
> > >   2  B  2  7  4
> > >   3  C  4  3  3
> > >   4  C  4  4  6
> > >   5  D  5  5  3",sep="",header=TRUE,stringsAsFactors=FALSE)
> > >
> > >
> > >  library(plyr)
> > >  ddply(dat,.(Name),numcolwise(mean,na.rm=TRUE))
> > > A.K.
> > >
> > >
> > > On Tuesday, May 27, 2014 4:08 PM, Verena Weinbir <vweinbir@gmail.com>
> > > wrote:
> > > Hello,
> > >
> > > I have a big dataframe, and want to average two specific cells of two
> > > specific rows and then replace those two rows with one row which
> > contains
> > > the averaged cells. Example (row 3 and 4: Cells2 and Cells3 averaged
> > and
> > > replaced)
> > >
> > >     NameC1 C2 C3
> > >   1  A  3  3  5
> > >   2  B  2  7  4
> > >   3  C  4  3  3
> > >   4  C  4  4  6
> > >   5  D  5  5  3
> > >
> > >
> > >
> > >     NameC1 C2  C3
> > >   1  A  3  3   5
> > >   2  B  2  7   4
> > >   3  C  4  3.5 4.5  4  D  5  5   3
> > >
> > >
> > > Many thanks in advance!
> > >
> > > Best,
> > >
> > > Verena
> > >
> > >     [[alternative HTML version deleted]]
> > >
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> >
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