I can confirm that the drop default is different, but keep in mind that it is only changed for a tbl_df so just convert back to data.frame at the end of your dplr operations to get back to your familiar data.frame behavior. --------------------------------------------------------------------------- Jeff Newmiller The ..... ..... Go Live... DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... Live: OO#.. Dead: OO#.. Playing Research Engineer (Solar/Batteries O.O#. #.O#. with /Software/Embedded Controllers) .OO#. .OO#. rocks...1k --------------------------------------------------------------------------- Sent from my phone. Please excuse my brevity.
On August 4, 2015 5:06:44 AM EDT, peter dalgaard <pda...@gmail.com> wrote: > >On 04 Aug 2015, at 10:50 , Karl Schilling <karl.schill...@uni-bonn.de> >wrote: > >> Dear All, >> >> I have an observation / question about how the function length() >works once package dplyr is loaded. >> >> Say we have a data.frame df with n rows and m columns. Then a way to >get the number of rows is to use >> >> length(df$m1) (m1 here stand is as the header of the first column) >> >> or, alternatively >> >> length(df[,1]). >> >> Both commands will return n. >> >> However, once dplyr is loaded, >> >> length(df[,1]) will return a value of 1. >> >> length(df$m1) and also length(df[[1]]) will correctly return n. >> >> I know that using length() may not be the most elegant or efficient >way to get the value of n. However, what puzzles (and somewhat >disturbs) me is that loading of dplyr affects how length() works, >without there being a warning or masking message upon loading it. >> >> Any clarification or comment would be welcome. > >Presumably, dplyr changes how [.data.frame works (by altering the >default for drop=, I expect) so that df[,1] is a data frame with 1 >variable and not a vector. And yes, that _is_ somewhat disturbing. > >-pd > >> >> Thank you so much, >> >> Karl >> >> >> -- >> Karl Schilling >> >> ______________________________________________ >> 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.