[R] simple question on data frames assignment

[PIKAL Petr]

Hi

> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Michael
> Artz
> Sent: Friday, April 8, 2016 3:50 AM
> To: Hadley Wickham <h.wickham at gmail.com>
> Cc: r-help at r-project.org
> Subject: Re: [R] simple question on data frames assignment
>
> Why am I better off with true and false?

I believe that because logical values can be transfered to numbers easily and you can use them directly to subset your object without any issue with numerical precision.

Cheers
Petr


>
> On Thu, Apr 7, 2016 at 8:41 AM, Hadley Wickham <h.wickham at gmail.com>
> wrote:
>
> > == is also vectorised, and you're better off with TRUE and FALSE
> > rather than 1 and 0, so I'd recommend:
> >
> > colordata$response <- colordata$color == 'blue'
> >
> > Hadley
> >
> > On Thu, Apr 7, 2016 at 6:52 AM, David Barron <dnbarron at gmail.com>
> wrote:
> > > ifelse is vectorised, so just use that without the loop.
> > >
> > > colordata$response <- ifelse(colordata$color == 'blue', 1, 0)
> > >
> > > David
> > >
> > > On 7 April 2016 at 12:41, Michael Artz <michaeleartz at gmail.com> wrote:
> > >
> > >> Hi I'm not sure how to ask this, but its a very easy question to
> > >> answer
> > for
> > >> an R person.
> > >>
> > >> What is an easy way to check for a column value and then assigne a
> > >> new column a value based on that old column value?
> > >>
> > >> For example, Im doing
> > >>  colordata <- data.frame(id = c(1,2,3,4,5), color = c("blue",
> > >> "red", "green", "blue", "orange"))  for (i in 1:nrow(colordata)){
> > >>    colordata$response[i] <- ifelse(colordata[i,"color"] == "blue",
> > >> 1, 0)  }
> > >>
> > >> which works,  but I don't want to use the for loop I want to "vecotrize"
> > >> this.  How would this be implemented?
> > >>
> > >>         [[alternative HTML version deleted]]
> > >>
> > >> ______________________________________________
> > >> 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.
> > >>
> > >
> > >         [[alternative HTML version deleted]]
> > >
> > > ______________________________________________
> > > 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.
> >
> >
> >
> > --
> > http://hadley.nz
> >
>
>       [[alternative HTML version deleted]]
>
> ______________________________________________
> 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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