[R] Data indexing issue...

Ivan Calandra ivan.calandra at u-bourgogne.fr
Tue Mar 27 13:43:09 CEST 2012

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.


Université de Bourgogne
UMR CNRS/uB 6282 Biogéosciences
6 Boulevard Gabriel
21000 Dijon, FRANCE
ivan.calandra at u-bourgogne.fr

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 at 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
> and provide commented, minimal, self-contained, reproducible code.

More information about the R-help mailing list