On Apr 8, 2010, at 9:47 AM, Jun Shen wrote:
Dear David, Erik and Charles,Thank you for your input. Both mapply() and which() can do the job. Just one exception. If there is a missing value as NA in the data frame "a" and a data point (either numerical or character) in the corresponding position of "b", then mapply() only returns NA for that position rather than "FALSE",and which() cannot pick up that position either. Thanks again.
You seem to have changed the programming challenge from identification to replicating identical(). If so then you can get closer with wrapping isTRUE(all() around the mapply("==" , attributes( ...), ...) step, and wrap the "==" call in isTRUE(all(.))
> isTRUE(all(mapply("==", df1, df2)) )
[1] FALSE since all(c(NA, TRUE, TRUE)) == NA and isTRUE(NA) == FALSE
--
David.
JunOn Wed, Apr 7, 2010 at 10:46 PM, Charles C. Berry <cbe...@tajo.ucsd.edu >wrote:On Wed, 7 Apr 2010, Jun Shen wrote: Dear all,I understand identical (a,b) will tell me if a and b are exactly the sameor not. But what if they are different, is there anyway to tell which element(s) are different? Thanks.which( a != b, arr.ind = TRUE) HTH, ChuckJun [[alternative HTML version deleted]] ______________________________________________ R-help@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.Charles C. Berry (858) 534-2098 Dept of Family/Preventive Medicine E mailto:cbe...@tajo.ucsd.edu UC San Diegohttp://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901[[alternative HTML version deleted]] ______________________________________________ R-help@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.
David Winsemius, MD West Hartford, CT ______________________________________________ R-help@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.
