Hi, Here is an implementation. More data are added. An extra column hasRain is added instead of replacing column Amount.
> rain Year Month Day Amount 1 1950 1 1 0.0 2 1950 1 2 35.5 3 1950 1 3 17.8 4 1950 1 4 24.5 5 1950 1 5 12.3 6 1950 1 6 11.5 7 1950 1 7 5.7 8 1950 1 8 13.2 9 1950 1 9 11.3 10 1950 1 10 14.7 11 1950 1 11 11.9 12 1950 1 12 17.5 13 1950 1 13 8.1 14 1950 1 14 0.4 15 1950 1 15 0.0 16 1950 1 16 19.5 17 1950 1 17 10.7 18 1950 1 18 0.5 19 1950 1 19 12.7 20 1950 1 20 6.3 21 1950 2 1 0.0 22 1950 2 2 35.5 23 1950 2 3 17.8 24 1950 2 4 24.5 25 1950 2 5 12.3 26 1950 2 6 11.5 27 1950 2 7 5.7 28 1950 2 8 13.2 29 1950 2 9 11.3 30 1950 2 10 14.7 31 1950 2 11 11.9 32 1950 2 12 17.5 33 1950 2 13 8.1 34 1950 2 14 0.4 35 1950 2 15 0.0 36 1950 2 16 19.5 37 1950 2 17 10.7 38 1950 2 18 0.0 39 1950 2 19 0.0 40 1950 2 20 0.0 > rain$hasRain <- ifelse(rain$Amount>0,1,0) > rain Year Month Day Amount hasRain 1 1950 1 1 0.0 0 2 1950 1 2 35.5 1 3 1950 1 3 17.8 1 4 1950 1 4 24.5 1 5 1950 1 5 12.3 1 6 1950 1 6 11.5 1 7 1950 1 7 5.7 1 8 1950 1 8 13.2 1 9 1950 1 9 11.3 1 10 1950 1 10 14.7 1 11 1950 1 11 11.9 1 12 1950 1 12 17.5 1 13 1950 1 13 8.1 1 14 1950 1 14 0.4 1 15 1950 1 15 0.0 0 16 1950 1 16 19.5 1 17 1950 1 17 10.7 1 18 1950 1 18 0.5 1 19 1950 1 19 12.7 1 20 1950 1 20 6.3 1 21 1950 2 1 0.0 0 22 1950 2 2 35.5 1 23 1950 2 3 17.8 1 24 1950 2 4 24.5 1 25 1950 2 5 12.3 1 26 1950 2 6 11.5 1 27 1950 2 7 5.7 1 28 1950 2 8 13.2 1 29 1950 2 9 11.3 1 30 1950 2 10 14.7 1 31 1950 2 11 11.9 1 32 1950 2 12 17.5 1 33 1950 2 13 8.1 1 34 1950 2 14 0.4 1 35 1950 2 15 0.0 0 36 1950 2 16 19.5 1 37 1950 2 17 10.7 1 38 1950 2 18 0.0 0 39 1950 2 19 0.0 0 40 1950 2 20 0.0 0 > tapply(rain$hasRain,list(rain$Year,rain$Month),sum) 1 2 1950 18 15 > -- View this message in context: http://r.789695.n4.nabble.com/Replace-the-value-with-1-and-0-tp4703838p4703840.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.