[R] Conditionally swap two columns of a data.frame?

[Dan Bolser]

On Thu, 16 Sep 2004, Dimitris Rizopoulos wrote:

>type "help.start()" in the R console or open manually the "C:\Program
>Files\R\rw1091\doc\html\rwin.html" file and you will get all the
>available on-line documentation that ships with each R installation.

That is the problem, you get it all ;)

Thanks though,
Dan.

>
>Best,
>Dimitris
>
>----
>Dimitris Rizopoulos
>Ph.D. Student
>Biostatistical Centre
>School of Public Health
>Catholic University of Leuven
>
>Address: Kapucijnenvoer 35, Leuven, Belgium
>Tel: +32/16/396887
>Fax: +32/16/337015
>Web: http://www.med.kuleuven.ac.be/biostat/
>     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm
>
>
>----- Original Message ----- 
>From: "Dan Bolser" <dmb at mrc-dunn.cam.ac.uk>
>To: "Dimitris Rizopoulos" <dimitris.rizopoulos at med.kuleuven.ac.be>
>Cc: <r-help at stat.math.ethz.ch>
>Sent: Thursday, September 16, 2004 2:55 PM
>Subject: Re: [R] Conditionally swap two columns of a data.frame?
>
>
>>
>> Minter!
>>
>> Is there an R cookbook? which lists this kind of common problem and
>common
>> solution?
>>
>>
>> On Thu, 16 Sep 2004, Dimitris Rizopoulos wrote:
>>
>> >Hi Dan,
>> >
>> >do you need something like that,
>> >
>> >dat <- data.frame(V1=rnorm(40000, 10), V2=rnorm(40000, 10))
>> >ratioV1V2 <- ifelse(dat$V1>dat$V2, dat$V1/dat$V2, dat$V2/dat$V1)
>> >
>> >I hope it helps.
>> >
>> >Best,
>> >Dimitris
>> >
>> >----
>> >Dimitris Rizopoulos
>> >Ph.D. Student
>> >Biostatistical Centre
>> >School of Public Health
>> >Catholic University of Leuven
>> >
>> >Address: Kapucijnenvoer 35, Leuven, Belgium
>> >Tel: +32/16/396887
>> >Fax: +32/16/337015
>> >Web: http://www.med.kuleuven.ac.be/biostat/
>> >     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm
>> >
>> >----- Original Message ----- 
>> >From: "Dan Bolser" <dmb at mrc-dunn.cam.ac.uk>
>> >To: <r-help at stat.math.ethz.ch>
>> >Sent: Thursday, September 16, 2004 2:19 PM
>> >Subject: [R] Conditionally swap two columns of a data.frame?
>> >
>> >
>> >>
>> >> I am doing this a kinda dumb way, and it is apparetnly taking
>> >> forever.
>> >>
>> >> I have a data frame with two numeric columns. I want to look at
>> >their
>> >> correlation, and I am looking at the size ratio between the two.
>> >>
>> >> i.e.
>> >>
>> >> plot(density(data$V1/data$V2))
>> >>
>> >> This kinda gives me a normal curve showing something about the
>> >> distribution of the two values.
>> >>
>> >> I want to make sure that V1/V2 is always > 1 ...
>> >>
>> >> for (i in 1:length(row.names(data)) ){
>> >>   ratioV1V2 <- if(V1>V2) V1/V2 else V2/V1
>> >> }
>> >>
>> >> This is a bit of a hack, and is taking forever for some reson
>(about
>> >> 40,000 rows in my data.frame).
>> >>
>> >> I would just like to swap the values in the data frame (to put
>the
>> >bigest
>> >> first for example), then use the above plot to get what I want.
>> >>
>> >> Should I use the DB backend to the data to make the dump in this
>> >way?
>> >> (involves some hacky sql)
>> >>
>> >> Considering I am interested in the range of the ratio between V1
>and
>> >V2,
>> >> should I be looking at doing a different analysis?
>> >>
>> >> I am so dumb, any help is appreciated,
>> >>
>> >> Dan.
>> >>
>> >> ______________________________________________
>> >> R-help at stat.math.ethz.ch mailing list
>> >> https://stat.ethz.ch/mailman/listinfo/r-help
>> >> PLEASE do read the posting guide!
>> >http://www.R-project.org/posting-guide.html
>> >>
>> >
>>
>