Thank you to Ozgur, who gave me the hints for an easy solution. There are the commands that work for my case: mean(my_dataframe$Freq[my_dataframe$month == 5 & my_dataframe$day %in% c(1:7)]) mean(my_dataframe$Freq[my_dataframe$month == 5 & my_dataframe$day %in% c(8:14)]) ... Stefano Sofia PhD This is the original message: Dear list users, I have a data frame as below specified.
Summary about how to divide data by week
2 messages · Stefano Sofia, Rui Barradas
Hello, I'm glad you have a solution that works. Maybe you could do the same without hard-coding the values 1:7, 8:14. $ library(chron) dat <- with(my_dataframe, paste(month, day, year, sep="/")) week <- cut(chron(dat), breaks="weeks") head(week) tapply(my_dataframe$Freq, week, mean) Hope this helps, Rui Barradas -- View this message in context: http://r.789695.n4.nabble.com/Summary-about-how-to-divide-data-by-week-tp4563909p4565199.html Sent from the R help mailing list archive at Nabble.com.