Thanks, Dimitri! It is really cool!

On Thu, Feb 24, 2011 at 11:43 AM, Dimitri Liakhovitski <
dimitri.liakhovitski@gmail.com> wrote:

> If your ack$ID variable is numeric, you could first turn it into a factor:
>
> myfactor = as.factor(ack$ID)
>
> And then use model.matrix to create dummy variables:
>
> mydummies = model.matrix(~myfactor)[, -1]
>
> You'll get as many dummy variables as values you have in ack$ID -
> minus 1 (for the reference level).
> Dimitri
>
> On Thu, Feb 24, 2011 at 2:30 PM, Changbin Du <changbind@gmail.com> wrote:
> > Thanks to all, appreciated!
> >
> > On Thu, Feb 24, 2011 at 11:18 AM, Jonathan P Daily <jdaily@usgs.gov>
> wrote:
> >
> >> See inline below.
> >> --------------------------------------
> >> Jonathan P. Daily
> >> Technician - USGS Leetown Science Center
> >> 11649 Leetown Road
> >> Kearneysville WV, 25430
> >> (304) 724-4480
> >> "Is the room still a room when its empty? Does the room,
> >>  the thing itself have purpose? Or do we, what's the word... imbue it."
> >>     - Jubal Early, Firefly
> >>
> >> r-help-bounces@r-project.org wrote on 02/24/2011 01:23:54 PM:
> >>
> >> > [image removed]
> >> >
> >> > [R] create dummy variables by for loop
> >> >
> >> > Changbin Du
> >> >
> >> > to:
> >> >
> >> > <r-help@r-project.org>
> >> >
> >> > 02/24/2011 01:25 PM
> >> >
> >> > Sent by:
> >> >
> >> > r-help-bounces@r-project.org
> >> >
> >> > HI, Dear R community,
> >> >
> >> > I try to create 100 dummy variables like the following:
> >> >
> >> > ack$id_1 <- (ack$ID==1)*1
> >> > ack$id_2 <- (ack$ID==2)*1
> >> > ..
> >> > .
> >> > ack$id_100 <- (ack$ID==100)*1
> >> >
> >> >
> >> > I used the following codes:
> >> >
> >> > for(i in 1:100){
> >> >               ack$id_[i] <- (ack$ID==i)*1
> >> >                      }
> >> This doesn't do what you think it does. when i = 1, it assigns the
> result
> >> of (ack$ID==1)*1 to the first element of ack$id_
> >>
> >> If you want ack$id_i to be created, try:
> >>
> >> ack[[paste("id", i, sep = "_")]] <- (ack$ID==i)*1
> >>
> >>
> >> >
> >> > But only one column is created, can anyone help me?
> >> >
> >> > Thanks a lot!
> >> >
> >> >
> >> > --
> >> > Sincerely,
> >> > Changbin
> >> > --
> >> >
> >>  >    [[alternative HTML version deleted]]
> >> >
> >> > ______________________________________________
> >> > R-help@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<http://www.r-project.org/posting-guide.html>
> <http://www.r-project.org/posting-guide.html>
>  >> > and provide commented, minimal, self-contained, reproducible code.
> >>
> >>
> >
> >
> > --
> > Sincerely,
> > Changbin
> > --
> >
> > Changbin Du
> > DOE Joint Genome Institute
> > Bldg 400 Rm 457
> > 2800 Mitchell Dr
> > Walnut Creet, CA 94598
> > Phone: 925-927-2856
> >
> >        [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@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<http://www.r-project.org/posting-guide.html>
> > and provide commented, minimal, self-contained, reproducible code.
> >
>
>
>
> --
> Dimitri Liakhovitski
> Ninah Consulting
> www.ninah.com
>



-- 
Sincerely,
Changbin
--

Changbin Du
DOE Joint Genome Institute
Bldg 400 Rm 457
2800 Mitchell Dr
Walnut Creet, CA 94598
Phone: 925-927-2856

	[[alternative HTML version deleted]]

