[R] Control the variable order after multiple declarations using within

Jeff Newmiller jdnewm|| @end|ng |rom dcn@d@v|@@c@@u@
Wed Jul 3 18:42:04 CEST 2019


Dummy columns do have some drawbacks though, if you find yourself working with large data frames. The dummy columns waste memory and time as compared to either reorganizing columns after the `within` or using separate sequential `with` expressions as I previously suggested. I think mutate avoids this overhead also.

On July 3, 2019 8:25:32 AM PDT, Eric Berger <ericjberger using gmail.com> wrote:
>Nice suggestion, Richard.
>
>On Wed, Jul 3, 2019 at 4:28 PM Richard O'Keefe <raoknz using gmail.com>
>wrote:
>
>> Why not set all the new columns to dummy values to get the order you
>> want and then set them to their final values in the order that works
>> for that?
>>
>>
>> On Thu, 4 Jul 2019 at 00:12, Kevin Thorpe <kevin.thorpe using utoronto.ca>
>> wrote:
>>
>> >
>> > > On Jul 3, 2019, at 3:15 AM, Sebastien Bihorel <
>> > sebastien.bihorel using cognigencorp.com> wrote:
>> > >
>> > > Hi,
>> > >
>> > > The within function can be used to modify data.frames (among
>other
>> > objects). One can even provide multiple expressions to modify the
>> > data.frame by more than one expression. However, when new variables
>are
>> > created, they seem to be inserted in the data.frame in the opposite
>order
>> > they were declared:
>> > >
>> > >> df <- data.frame(a=1)
>> > >> within(df, {b<-a*2; c<-b*3})
>> > >  a c b
>> > > 1 1 6 2
>> > >
>> > > Is there a way to insert the variables in an order consistent
>with the
>> > order of declaration (ie, a, b, c)?
>> > >
>> >
>> > One way is to use mutate() from the dplyr package.
>> >
>> >
>> > > Thanks
>> > >
>> > > Sebastien
>> > >
>> > > ______________________________________________
>> > > 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.
>> >
>> >
>> > --
>> > Kevin E. Thorpe
>> > Head of Biostatistics,  Applied Health Research Centre (AHRC)
>> > Li Ka Shing Knowledge Institute of St. Michael's
>> > Assistant Professor, Dalla Lana School of Public Health
>> > University of Toronto
>> > email: kevin.thorpe using utoronto.ca  Tel: 416.864.5776  Fax:
>416.864.3016
>> >
>> > ______________________________________________
>> > 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.
>> >
>>
>>         [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> 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.
>>
>
>	[[alternative HTML version deleted]]
>
>______________________________________________
>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.

-- 
Sent from my phone. Please excuse my brevity.



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