Hi, On Fri, Apr 30, 2010 at 12:08 PM, Jeff Brown <dopethatwantsc...@yahoo.com>wrote:
> > Hi, > > I still have little ability to predict how these functions will treat the > columns of data frames: > > > # Here's a data frame with a column "a" of integers, > > # and a column "b" of characters: > > df <- data.frame( > + a = 1:2, > + b = c("a","b") > + ) > > df > a b > 1 1 a > 2 2 b > > > > # Except -- both columns are characters: > > apply (df, 2, typeof) > a b > "character" "character" > apply converts all to character > > > > # Except -- they're both integers: > > lapply (df, typeof) > $a > [1] "integer" > > $b > [1] "integer" > > data.frame has a argument 'stringsAsFactors', this converts character columns to factor columns. Factors are integers with labels > > > > # Except -- only one of those integers is numeric: > > lapply (df, is.numeric) > $a > [1] TRUE > > $b > [1] FALSE > df$b is a factor. > > > Many thanks, > Jeff > -- > View this message in context: > http://r.789695.n4.nabble.com/Why-do-data-frame-column-types-vary-across-apply-lapply-tp2077054p2077054.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. > -- Henrique Dallazuanna Curitiba-Paraná-Brasil 25° 25' 40" S 49° 16' 22" O [[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.