Thank you Jeff and Rainer. I will try Jeff's idea using the sub string. function to extract the year and split on that.
Thanks again to both--EK On Sat, Mar 16, 2019 at 1:52 AM Jeff Newmiller <jdnew...@dcn.davis.ca.us> wrote: > > Couldn't you just use the substr function to pull the year out yourself to > make the grouping column? > > On March 15, 2019 10:40:01 PM PDT, Ek Esawi <esaw...@gmail.com> wrote: > >Hi All— > > > >I have a data frame with over 13000 rows and 4 columns. A mini data > >frame is given at the bottom. I want to split the data frame into > >lists each corresponds to single year which ranges from 1990 to 2018). > >I wanted to use the split function, but it requires a vector of the > >same length as MyDate which contains many multiples of each year. > >Any help is highly appreciated. > > > >I want the following results: > >List 1990 > >MyDate MyNo MyDes > >1990 > >1990 > >1990 > >…... > >List 2000 > >2000 > >2000 > >2000 > >…... > >List 2001 > >2001 > >2001 > >2001 > >2001 > >…... > >List 2018 > >2018 > >2018 > >2018 > >…... > > > >Sample data frame > > > >mydf <- > >data.frame(MyDate=c("1990-01-01","1990-04-07","2000-04-05","2018-01-04"),MyNo=c(1,2,3,4),MyDes=c("AA","BB","CC","DD")) > > > > > >EK > > > >______________________________________________ > >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. > > -- > Sent from my phone. Please excuse my brevity. ______________________________________________ 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.