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.