Hi Andy, I believe this is because R 4.0 has changed the default behavior of data.frame(). Prior to 4.0, the default was stringsAsFactors=TRUE. In 4.0, the default is stringsAsFactors=FALSE.
If you run your code in R 3.6.1 and change the command to data <- data.frame(name,values,stringsAsFactors=FALSE) you will get the same behavior as in R 4.0. HTH, Eric On Wed, Jul 15, 2020 at 6:45 PM andy elprama <andy.elpr...@gmail.com> wrote: > Dear R-users, > > Something strange happened within the command "levels" > > R version 3.6.1 > name <- c("a","b","c") > values <- c(1,2,3) > data <- data.frame(name,values) > levels(data$name) > [1] "a" "b" "c" > > R version 4.0 > name <- c("a","b","c") > values <- c(1,2,3) > data <- data.frame(name,values) > levels(data$name) > [1] NULL > > What is happening here? > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. > [[alternative HTML version deleted]] ______________________________________________ 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.