How about DT[, .N , by = .(student_fee)] mån 16 okt. 2017 kl. 12:00 skrev < [email protected]>:
> Send datatable-help mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help > > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of datatable-help digest..." > > > Today's Topics: > > 1. how to grouping of data in R (memonsalim2008) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Mon, 16 Oct 2017 01:34:10 -0700 (MST) > From: memonsalim2008 <[email protected]> > To: [email protected] > Subject: [datatable-help] how to grouping of data in R > Message-ID: <[email protected]> > Content-Type: text/plain; charset=us-ascii > > Hi All, > > is it possible in R groping of data ?Please check blow example. > > > student_id Fee > 5555 1200 > 5555 1200 > 1111 1200 > 6666 1500 > 6666 1500 > 6666 1000 > 7777 1000 > 8888 1000 > 8888 1000 > 8888 1000 > 8888 1000 > > output of will be > > student_id count > 5555 2 > 1111 1 > 6666 3 > 7777 1 > 8888 4 > > > > > > -- > Sent from: http://r.789695.n4.nabble.com/datatable-help-f2315188.html > > > ------------------------------ > > _______________________________________________ > datatable-help mailing list > [email protected] > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help > > End of datatable-help Digest, Vol 92, Issue 6 > ********************************************* >
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