Dear all, Lets say I have a data frame as follows:
> Date <- as.Date(c('2006-08-23', '2006-08-30', '2006-09-06', '2006-09-13', > '2006-09-20')) > Income <- c(73.79, 72.46, 76.32, 72.43, 72.62) > data.frame(Date, Income) Date Income 1 2006-08-23 73.79 2 2006-08-30 72.46 3 2006-09-06 76.32 4 2006-09-13 72.43 5 2006-09-20 72.62 > is there a way to group the data by month (summing the values in each month), i.e. Date Income 2006-08 146.25 2006-09 221.37 Thanks in advance, C.C. ______________________________________________ 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.