Re: [R] dplyr and function length()
Dear Jeff: No, the effect I described has nothing to do wit USING dplyr. It occurs with any (preexisting) data.frame once dplyr is LOADED (require(dplyr). It is this silent, sort of backward acting effect that disturbs me. Best, Karl Schilling On 04.08.2015 12:20, Jeff Newmiller wrote: 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 NewmillerThe . . Go Live... DCN:jdnew...@dcn.davis.ca.us Basics: ##.#. ##.#. Live Go... Live: OO#.. Dead: OO#.. Playing Research Engineer (Solar/BatteriesO.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 dalgaardpda...@gmail.com wrote: On 04 Aug 2015, at 10:50 , Karl Schillingkarl.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 -- 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.
Re: [R] dplyr and function length()
No, the effect I described has nothing to do wit USING dplyr. It occurs with any (preexisting) data.frame once dplyr is LOADED (require(dplyr). It is this silent, sort of backward acting effect that disturbs me. You're going to need to provide some evidence for that charge: dplyr does not affect the behaviour of data.frames (only tbl_dfs) Hadley -- http://had.co.nz/ __ 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.
Re: [R] dplyr and function length()
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. It changes the behaviour for [.tbl_df (tbl_df is a very minor extension of data frame with custom [ and print methods). This is partly an experiment to see what happens when you make [ more consistent - [.tbl_df always returns a data frame, so if you want a vector you have to use [[. Hadley -- http://had.co.nz/ __ 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.
Re: [R] dplyr and function length() and some apologies
Dear Hadley: your request for evidence for my observation seems to have paved the way to solve this issue. As it turns out, the effect I described only occurs with data.frames read in with readxl. Clearly, I missed that these are tbl_df. And that explains the differential behavior depending on whether dplyr is loaded or not. Also, I realize that this latter effect can be avoided by explicitly converting objects read in with readxl to a data.frame. Well, I should have known that if i had carefully read the README stuff for readxl. But then, readxl is so much of an every-day tool for me that I didn't even think of its involvement in my problem, all the more as the reference manual does not mention the format/class of objects read in with readxl. So my apologies for any confusion I may have caused - and I certainly did not mean my observation as a charge against dplyr or its authors. Quite to the contrary, i appreciate thees tools, and as you may see, tray to understand and use them. Thank you so much again Karl On 04.08.2015 13:14, Hadley Wickham wrote: No, the effect I described has nothing to do wit USING dplyr. It occurs with any (preexisting) data.frame once dplyr is LOADED (require(dplyr). It is this silent, sort of backward acting effect that disturbs me. You're going to need to provide some evidence for that charge: dplyr does not affect the behaviour of data.frames (only tbl_dfs) Hadley -- 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] dplyr and function length()
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$m1) and also length(df[[1]]) will correctly return n. I know that using length() may not be the most elegant or efficient way to get the value of n. However, what puzzles (and somewhat disturbs) me is that loading of dplyr affects how length() works, without there being a warning or masking message upon loading it. Any clarification or comment would be welcome. Thank you so much, Karl -- Karl Schilling __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] dplyr and function length()
On 04 Aug 2015, at 10:50 , Karl Schilling karl.schill...@uni-bonn.de wrote: Dear All, I have an observation / question about how the function length() works once package dplyr is loaded. Say we have a data.frame df with n rows and m columns. Then a way to get the number of rows is to use length(df$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. -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd@cbs.dk Priv: pda...@gmail.com __ 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.
Re: [R] dplyr and function length()
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 NewmillerThe . . Go Live... DCN:jdnew...@dcn.davis.ca.usBasics: ##.#. ##.#. Live Go... Live: OO#.. Dead: OO#.. Playing Research Engineer (Solar/BatteriesO.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.
