Hi All, I am trying to sort dates within a group. My sample data is
df <-read.table(text="ID date A1 09/17/04 A1 01/27/05 A1 05/07/03 A2 05/21/17 A2 09/12/16 A3 01/25/13 A4 09/27/19",header=TRUE,stringsAsFactors=F) df$date2 = as.Date(strptime(df$date,format="%m/%d/%y")) df$date =NULL I want to sort date2 from recent to oldest. within the ID group and I used this, df <- df[order(df$ID, rev((df$date2))),]. It did not work and teh output is shown below. ID date2 2 A1 2005-01-27 3 A1 2003-05-07 1 A1 2004-09-17 5 A2 2016-09-12 4 A2 2017-05-21 6 A3 2013-01-25 7 A4 2019-09-27 What am I missing? Thank you. ______________________________________________ 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.
