A reproducible example was not provided, but I think what is wanted is either ?tapply or ?ave; e.g.
within(DF, means <- ave(total, note, month, FUN = mean)) Cheers, Bert 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 Sat, Nov 26, 2016 at 3:42 PM, P Tennant <philipt...@iinet.net.au> wrote: > Hi, > > It may help that: > > aggregate(DF$total, list(DF$note, DF$id, DF$month), mean) > > should give you means broken down by time slice (note), id and month. You > could then subset means for GA or GB from the aggregated dataframe. > > Philip > > On 27/11/2016 3:11 AM, lily li wrote: >> >> Hi R users, >> >> I'm trying to manipulate a dataframe and have some difficulties. >> >> The original dataset is like this: >> >> DF >> year month total id note >> 2000 1 98 GA 1 >> 2001 1 100 GA 1 >> 2002 2 99 GA 1 >> 2002 2 80 GB 1 >> ... >> 2012 1 78 GA 2 >> ... >> >> The structure is like this: when year is between 2000-2005, note is 1; >> when >> year is between 2006-2010, note is 2; GA, GB, etc represent different >> groups, but they all have years 2000-2005, 2006-2010, 2011-2015. >> I want to calculate one average value for each month in each time slice. >> For example, between 2000-2005, when note is 1, for GA, there is one value >> in month 1, one value in month 2, etc; for GB, there is one value in month >> 1, one value in month 2, between this time period. So later, there is no >> 'year' column, but other columns. >> I tried the script: DF_GA = aggregate(total~year+month,data=subset(DF, >> id==GA¬e==1)), but it did not give me the ideal dataframe. How to do >> then? >> Thanks for your help. >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org 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. > > > ______________________________________________ > R-help@r-project.org 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. ______________________________________________ R-help@r-project.org 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.
