Re: [R] splitting data frame based on a criteria

From: Moshe Olshansky <m_olshansky_at_yahoo.com>
Date: Tue, 03 Jun 2008 16:31:30 -0700 (PDT)


Also check ?aggregate

> From: Ingmar Visser <i.visser_at_uva.nl>
> Subject: Re: [R] splitting data frame based on a criteria
> To: "Marvin Lists" <marvin.lists_at_gmail.com>
> Cc: r-help_at_r-project.org
> Received: Wednesday, 4 June, 2008, 5:11 AM
> ?by may be helpful here
> eg if dat is your data.frame and yf is a factor (created
> using ifelse)
> use by(dat,yf,mean) to compute the means for each level of
> yf
> hth, Ingmar
>
> On Jun 3, 2008, at 8:37 PM, Marvin Lists wrote:
>
> > Hi,
> > I have a data frame that I want to split into two
> based on the
> > values of a
> > variable in it.
> >
> > The variable Y has numeric values ranging between 0
> through 70. I
> > want to
> > plot the frequencies of another variable X in two
> different cases:
> > - When Y = 0 and
> > - When Y > 0
> >
> > How does one go about doing this?
> >
> > In general, I want to do several analyses with this
> data frame that
> > are a
> > variation of the above situation, i.e. they require
> splitting the
> > data into
> > different age, gender etc. and then calculating
> separate means,
> > correlations
> > and so on for the different groups into which the data
> frame would
> > split.
> >
> > I am struggling with the correct syntax for achieving
> this.
> >
> > Reading through the documentation suggests that tapply
> and split
> > may be the
> > functions to use for my purposes but the examples in
> the
> > documentations
> > didn't help me understand how I could achieve
> this.
> >
> > I would appreciate any suggestions and help.
> >
> > Thanks,
> > Marvin
> >
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help_at_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.
>
> ______________________________________________
> R-help_at_r-project.org mailing list
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> PLEASE do read the posting guide
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> and provide commented, minimal, self-contained,
> reproducible code.



R-help_at_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. Received on Tue 03 Jun 2008 - 23:36:21 GMT

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