[R] by group

[Val]

Thank you all!
I can assure you that this is not  HW. This is a sample of my large
data set and I want a simple  and efficient approach to get the
desired  output   in that particular format.  That file will be saved
and used  as an input file for another external process.

val







On Mon, Nov 1, 2021 at 6:08 PM Avi Gross via R-help
<r-help using r-project.org> wrote:
>
> Jim,
>
> Your code gives the output in quite a different format and as an object of
> class "by" that is not easily convertible to a data.frame. So, yes, it is an
> answer that produces the right numbers but not in the places or data
> structures I think they (or if it is HW ...) wanted.
>
> Trivial standard cases are often handled by a single step but more complex
> ones often suggest a multi-part approach.
>
> Of course Val gets to decide what approach works best for them within
> whatever constraints we here are not made aware of. If this is a class
> assignment, it likely would be using only tools discussed in the class. So I
> would not suggest using a dplyr/tidyverse approach if that is not covered or
> even part of a class. If this is a project in the real world, it becomes a
> matter of programming taste and convenience and so on.
>
> Maybe Val can share more about the situation so we can see what is helpful
> and what is not. Realistically, I can think of way too many ways to get the
> required output.
>
> -----Original Message-----
> From: R-help <r-help-bounces using r-project.org> On Behalf Of Jim Lemon
> Sent: Monday, November 1, 2021 6:25 PM
> To: Val <valkremk using gmail.com>; r-help mailing list <r-help using r-project.org>
> Subject: Re: [R] by group
>
> Hi Val,
> I think you answered your own question:
>
> by(dat$wt,dat[,c("Sex","Year")],mean)
>
> Jim
>
> On Tue, Nov 2, 2021 at 8:09 AM Val <valkremk using gmail.com> wrote:
> >
> > Hi All,
> >
> > How can I generate mean by group. The sample data looks like as
> > follow, dat<-read.table(text="Year Sex wt
> > 2001 M 15
> > 2001 M 14
> > 2001 M 16
> > 2001 F 12
> > 2001 F 11
> > 2001 F 13
> > 2002 M 14
> > 2002 M 18
> > 2002 M 17
> > 2002 F 11
> > 2002 F 15
> > 2002 F 14
> > 2003 M 18
> > 2003 M 13
> > 2003 M 14
> > 2003 F 15
> > 2003 F 10
> > 2003 F 11  ",header=TRUE)
> >
> > The desired  output  is,
> >              M        F
> > 2001    15        12
> > 2002    16.33   13.33
> > 2003    15          12
> >
> > Thank you,
> >
> > ______________________________________________
> > R-help using 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.
>
> ______________________________________________
> R-help using 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.
>
> ______________________________________________
> R-help using 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.