I've read ?aggregate and several blog posts on using aggregate() yet I still haven't applied it correctly to my dataframe. The sample data are:
structure(list(sampdate = c("2005-01-01", "2005-01-02", "2005-01-03", "2005-01-04", "2005-01-05", "2005-01-06", "2005-01-07", "2005-01-08", "2005-01-09", "2005-01-10", "2005-01-11", "2005-01-12", "2005-01-13", "2005-01-14", "2005-01-15", "2005-01-16", "2005-01-17", "2005-01-18", "2005-01-19", "2005-01-20", "2005-01-21", "2005-01-22", "2005-01-23", "2005-01-24", "2005-01-25", "2005-01-26", "2005-01-27", "2005-01-28", "2005-01-29", "2005-01-30", "2005-01-31", "2005-02-01", "2005-02-02", "2005-02-03", "2005-02-04", "2005-02-05", "2005-02-06", "2005-02-07", "2005-02-08", "2005-02-09", "2005-02-10", "2005-02-11", "2005-02-12", "2005-02-13", "2005-02-14", "2005-02-15", "2005-02-16", "2005-02-17", "2005-02-18", "2005-02-19", "2005-02-20", "2005-02-21", "2005-02-22", "2005-02-23", "2005-02-24", "2005-02-25", "2005-02-26", "2005-02-27", "2005-02-28", "2005-03-01", "2005-03-02", "2005-03-03"), prcp = c(0.59, 0.08, 0.1, 0, 0, 0.02, 0.05, 0.1, 0, 0.02, 0, 0.05, 0.2, 0, 0, 0.5, 0.41, 0.84, 0.01, 0.1, 0.01, 0, 0, 0, 0, 0.21, 0.24, 0.13, 1.12, 0.01, 0.09, 0, 0, 0, 0.35, 0.18, 0.65, 0.16, 0, 0, 0, 0, 0.55, 0.21, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0.17, 0.05, 0.01, 0)), row.names = c(NA, 62L), class = "data.frame")
What I need to learn how to do is to calculate monthly sum, median, and maximum rainfall amounts from the full data set which has daily rainfall amounts. My most current effort to calculate monthly sums uses this syntax: monthly.rain <- aggregate.ts(x = dp['sampdate','prcp'], by = list(month = \ substr(dp$sampdate, 1, 7)), FUN = sum, na.rm = TRUE) (entered on a single line) which produces this result: head(monthly.rain) [1] NA The sample data has 62 of the 113K rows in the dataframe. A larger set can be provided if needed. An explanation of what I've missed is needed. Regards, Rich ______________________________________________ [email protected] mailing list -- To UNSUBSCRIBE and more, see 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.
