Why does one method work, and the other not? attach(iris) head(iris)
mean(Sepal.Length) [1] 5.843333 apply(iris, Sepal.Length, mean) "Error in if (d2 == 0L) { : missing value where TRUE/FALSE needed" I seem to get this error frequently with the apply functions but other "manual" methods work normally on the same data. TIA -- View this message in context: http://r.789695.n4.nabble.com/apply-question-tp3821122p3821122.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.