Clarification: When using the formula interface, no subscripting is needed.
Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Fri, Sep 7, 2018 at 3:25 PM Bert Gunter <[email protected]> wrote: > > Well, let's see: > "monthly.rain <- aggregate.ts(x = dp['sampdate','prcp'], by = list(month = \ > substr(dp$sampdate, 1, 7)), FUN = sum, na.rm = TRUE)" > > 1. x is a data frame, so why are you using the time series method? > Perhaps you need to study S3 method usage in R. > > 2. You have improperly subscripted the data frame: it should be dp[, > c('sampdate','prcp')] . Perhaps you need to read about how > subscripting in R. However, in this case, no subscripting is needed > (see 3.) > > 3. As you should be using the data frame method, and the month is > obtained as a substring of sampdate, you should use dp[,'prcp'] as > your data frame so that sum() is not applied to the sampdate column. > > 4. I assume the "\" indicates <Return> ? > > Anyway, once you have corrected all that, here's the call: > > > monthly.rain <- aggregate(dp[, 'prcp'], > + list(substr(dp$sampdate,1,7)), > + FUN = sum, na.rm = TRUE) > > ## yielding > > monthly.rain > Group.1 x > 1 2005-01 4.88 > 2 2005-02 2.27 > 3 2005-03 0.06 > > It's perhaps also worth noting that the formula method (for data > frames) is somewhat more convenient, especially with several grouping > factors in the list: > > > monthly.rain <- aggregate(prcp ~ substr(sampdate,1,7), data = dp, FUN = > > sum, na.rm = TRUE) > > ##yielding > > monthly.rain > substr(sampdate, 1, 7) prcp > 1 2005-01 4.88 > 2 2005-02 2.27 > 3 2005-03 0.06 > > Cheers, > > Bert Gunter > > "The trouble with having an open mind is that people keep coming along > and sticking things into it." > -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) > On Fri, Sep 7, 2018 at 2:19 PM Rich Shepard <[email protected]> wrote: > > > > 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. ______________________________________________ [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.
