Hi Jim!

Thank you so much for the very helpful hints!!
I am learning 'split' now and it seems very useful..

HJ

On Tue, Mar 27, 2012 at 12:58 PM, jim holtman <jholtman@gmail.com> wrote:

> Why not use 'split' and get all the groups at once:
>
> result <- split(Calandra, list(Calandra$Day, Calandra$Season, drop = TRUE)
>
> On Tue, Mar 27, 2012 at 7:43 AM, Ivan Calandra
> <ivan.calandra@u-bourgogne.fr> wrote:
> > Hi HJ,
> >
> > Take a look at ?"&"; this is probably what you're looking for.
> >
> > What you could also do is:
> > Calender[Calender$Day=='Wd' & Calender$Season=="Winter", ]  # notice the
> > last comma
> >
> > This will subset directly without using which(); it might be helpful to
> you.
> >
> > HTH,
> > Ivan
> >
> > --
> > Ivan CALANDRA
> > Université de Bourgogne
> > UMR CNRS/uB 6282 Biogéosciences
> > 6 Boulevard Gabriel
> > 21000 Dijon, FRANCE
> > +33(0)3.80.39.63.06
> > ivan.calandra@u-bourgogne.fr
> > http://biogeosciences.u-bourgogne.fr/calandra
> >
> >
> > Le 27/03/12 12:32, HJ YAN a écrit :
> >
> >> Dear R-help,
> >>
> >> My dataset (which is a data frame, called 'Calender' here)  includes 365
> >> rows representing 365 days for a year.  One column ('Season')contains
> >> factor data representing seasons, e.g. spring, summer, autumn and
> winter.
> >> Another column (called 'Day') contains data representing wether the day
> >>  is
> >> a working day  (I use 'Wd' for short here)or weekend (I use 'Wkend' for
> >> short here).
> >>
> >>
> >> I want to seperate the index of the working days  and weekends for each
> >> season. I used R commend "which" before for one criteria, for example,
> if
> >> I
> >> use...
> >>
> >>
> >> WdIndex<-which(Calender$Day=='Wd')
> >>
> >> that will gives a set of indeices of working days in the year.
> >>
> >> I wonder in R could I use a combination of something such as 'AND' ,
> 'OR'
> >> (e.g. in MySQL) to set 'multi-criteria'  when selecting data. So for
> >> example...
> >>
> >> WinterWdIndex<-which(Calender$Day=='Wd' AND Calender$Season=="Winter")
> >>
> >>
> >> I know the above syntax is wrong, and I checked '?which' which did not
> >> give
> >> me an answer and also tried '?AND' but seems it doesn`t exist at all...
> >>
> >>
> >> Many thanks!
> >> HJ
> >>
> >>        [[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.
> >>
> >>
> >
> > ______________________________________________
> > 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.
>
>
>
> --
> Jim Holtman
> Data Munger Guru
>
> What is the problem that you are trying to solve?
> Tell me what you want to do, not how you want to do it.
>
> ______________________________________________
> 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.
>

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