How to reference previous row?
Hello, The solution to problem will seem far easier if you think in a different way. For instance, you may want to consider the extra dummy column previous.first.value <- c( "NA", first[ - length(first) ] ) Then you can "horizontally" compare first with it's previous value. Best regards, Carlos J. Gil Bellosta http://www.datanalytics.com
On Mon, 2009-01-12 at 18:57 +1100, Heston Capital wrote:
I am trying to write some code where the factor references its previous value, but can't find a solution searching through the archive.
X
first second 1 A 1 2 A 2 3 B 3 4 B 4 5 B 5 6 C 6 7 C 7 I need a third column, in pseudo code- If value of first=previous value of first: third=previous value of third else third = second So the third column would look like: 0 0 3 3 3 6 6 Thanks!
______________________________________________ R-help at r-project.org mailing list 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.