You will get this error if 'df' does not have columns named "X" and "Y", so df$X or df$Y is NULL. E.g., > df <- data.frame(One=1:3, Two=11:13) > df$Three <- df$One + df$noSuchColumn Error in `$<-.data.frame`(`*tmp*`, "Three", value = numeric(0)) : replacement has 0 rows, data has 3
What does names(df) show in the different panels? Bill Dunlap TIBCO Software wdunlap tibco.com On Sat, Mar 11, 2017 at 10:50 AM, lily li <chocol...@gmail.com> wrote: > Hi R users, > > I have a problem about using R studio. For example, there is a dataframe > that has many columns. I want to aggregated column X and column Y into > column Z. Column Z does not exist before the aggregation. I use the code > below: > df$Z = df$X + df$Y > > However, it does not work in the top left panel in Rstudio, and has the > following warning message: > Error in `$<-.data.frame`(`*tmp*`, "Z", value = numeric(0)) : > replacement has 0 rows, data has 34333 > > If I type the same code in the Console panel (bottom left panel), it works. > How to deal with this problem? Thanks. > > [[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. ______________________________________________ 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.