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