Gerrit
Changed my approach 😊 df <- data.frame(ID=1:5,Score=4*2:6) df %>% mutate(score_diff = Score - lag(Score, default = 0)) Jeff -----Original Message----- From: R-help <r-help-boun...@r-project.org> On Behalf Of Gerrit Eichner Sent: Wednesday, March 24, 2021 11:53 AM To: r-help@r-project.org Subject: Re: [R] Calculating column differences Dear Jeff, read diff's help page, and you'll find out what is wrong with your expectation. What do think diff(df$Score) should give for the first element in df$Score?? Hth -- Gerrit --------------------------------------------------------------------- Dr. Gerrit Eichner Mathematical Institute, Room 212 <mailto:gerrit.eich...@math.uni-giessen.de> gerrit.eich...@math.uni-giessen.de Justus-Liebig-University Giessen Tel: +49-(0)641-99-32104 Arndtstr. 2, 35392 Giessen, Germany <http://www.uni-giessen.de/eichner> http://www.uni-giessen.de/eichner --------------------------------------------------------------------- Am 24.03.2021 um 17:48 schrieb Jeff Reichman: > r-help forum > > > > I'm trying to calculate the diff between two rows and them mutate the > difference into a new column. I'm using the diff function but not > giving me what I want. > > > > df <- data.frame(ID=1:5,Score=4*2:6) > > > > What a want where > > ID Score diff > > 1 1 8 8 > > 2 2 12 4 > > 3 3 16 4 > > 4 4 20 4 > > 5 5 24 4 > > > > What I am getting > > ID Score diff > > 1 1 8 NA > > 2 2 12 4 > > 3 3 16 4 > > 4 4 20 4 > > 5 5 24 4 > > > > Jeff > > > > > [[alternative HTML version deleted]] > > ______________________________________________ > <mailto:R-help@r-project.org> R-help@r-project.org mailing list -- To > UNSUBSCRIBE and more, see > <https://stat.ethz.ch/mailman/listinfo/r-help> > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > <http://www.R-project.org/posting-guide.html> > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ <mailto:R-help@r-project.org> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see <https://stat.ethz.ch/mailman/listinfo/r-help> https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide <http://www.R-project.org/posting-guide.html> http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. [[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.
