search for: winterwdindex

...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]...