Sorry to ask such a simple question, but I can't find the answer after extensive searching the docs and the web. How do you remove a component from a list? For example say you have: lst<-c(5,6,7,8,9) How do you remove, for example, the third component in the list? lst[[3]]]<-NULL generates an error: "Error: more elements supplied than there are to replace" Also, how do you remove a row from a data frame? For example, say you have: lst1<-c(1,2,3,4,5) lst2<-c(6,7,8,9,10) frame<-data.frame(lst1,lst2) How do you remove, for example, the second row of frame? Thanks, - Jason
The first example you provide is a vector, not a list. You can remove the third element with: > lst[-3] [1] 5 6 8 9 The same thing works for rows of data frames: > frame[-3,] lst1 lst2 1 1 6 2 2 7 4 4 9 5 5 10> > > On 08/02/07, Jason Horn <jhorn at bu.edu> wrote: > > Sorry to ask such a simple question, but I can't find the answer after > > extensive searching the docs and the web. > > > > How do you remove a component from a list? For example say you have: > > > > lst<-c(5,6,7,8,9) > > > > How do you remove, for example, the third component in the list? > > > > lst[[3]]]<-NULL generates an error: "Error: more elements supplied > > than there are to replace" > > > > > > > > Also, how do you remove a row from a data frame? For example, say you > > have: > > > > lst1<-c(1,2,3,4,5) > > lst2<-c(6,7,8,9,10) > > frame<-data.frame(lst1,lst2) > > > > How do you remove, for example, the second row of frame? > > > > Thanks, > > > > - Jason > > > > ______________________________________________ > > R-help at stat.math.ethz.ch mailing list > > 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. > > > > > > -- > ================================> David Barron > Said Business School > University of Oxford > Park End Street > Oxford OX1 1HP-- ================================David Barron Said Business School University of Oxford Park End Street Oxford OX1 1HP
Hi Jason, On 2/8/07, Jason Horn <jhorn at bu.edu> wrote:> Sorry to ask such a simple question, but I can't find the answer after > extensive searching the docs and the web. > > How do you remove a component from a list? For example say you have:You use the - operator for both your vector and data frame examples.> lst <- c(5,6,7,8,9)# which by the way isn't a list> is.list(lst)[1] FALSE> lst[1] 5 6 7 8 9> lst <- lst[-3] > lst[1] 5 6 8 9> lst1<-c(1,2,3,4,5) > lst2<-c(6,7,8,9,10) > frame<-data.frame(lst1,lst2) > framelst1 lst2 1 1 6 2 2 7 3 3 8 4 4 9 5 5 10> frame[-2,]lst1 lst2 1 1 6 3 3 8 4 4 9 5 5 10 -- Sarah Goslee http://www.functionaldiversity.org
On 2/8/2007 12:30 PM, Jason Horn wrote:> Sorry to ask such a simple question, but I can't find the answer after > extensive searching the docs and the web. > > How do you remove a component from a list? For example say you have: > > lst<-c(5,6,7,8,9)In R jargon, that's a vector, not a list.> > How do you remove, for example, the third component in the list?lst[-3] will do it.> > lst[[3]]]<-NULL generates an error: "Error: more elements supplied > than there are to replace"The [[ index ]] syntax only works on true lists.> > > > Also, how do you remove a row from a data frame? For example, say you > have: > > lst1<-c(1,2,3,4,5) > lst2<-c(6,7,8,9,10) > frame<-data.frame(lst1,lst2) > > How do you remove, for example, the second row of frame?Same idea: frame <- frame[-2, ] Duncan Murdoch> > Thanks, > > - Jason > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > 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.
First: lst <- lst[-3] Second: frame<- frame[-2,] On 08/02/07, Jason Horn <jhorn@bu.edu> wrote:> > Sorry to ask such a simple question, but I can't find the answer after > extensive searching the docs and the web. > > How do you remove a component from a list? For example say you have: > > lst<-c(5,6,7,8,9) > > How do you remove, for example, the third component in the list? > > lst[[3]]]<-NULL generates an error: "Error: more elements supplied > than there are to replace" > > > > Also, how do you remove a row from a data frame? For example, say you > have: > > lst1<-c(1,2,3,4,5) > lst2<-c(6,7,8,9,10) > frame<-data.frame(lst1,lst2) > > How do you remove, for example, the second row of frame? > > Thanks, > > - Jason > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > 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. >-- Henrique Dallazuanna Curitiba-Paraná Brasil [[alternative HTML version deleted]]
Jason Horn wrote:> Sorry to ask such a simple question, but I can't find the answer after > extensive searching the docs and the web. > > How do you remove a component from a list? For example say you have: > > lst<-c(5,6,7,8,9) > > How do you remove, for example, the third component in the list?Is the object lst really a list? Try is.list(lst) to check. To remove an element from a vector, use for example, lst[-3]> > lst[[3]]]<-NULL generates an error: "Error: more elements supplied > than there are to replace" > >If lst were actually a list, that command would work with the obvious syntax fix. So would lst[-3] though.> > Also, how do you remove a row from a data frame? For example, say you > have: > > lst1<-c(1,2,3,4,5) > lst2<-c(6,7,8,9,10) > frame<-data.frame(lst1,lst2) > > How do you remove, for example, the second row of frame?You use frame[-2, ] #remove second row, keep all columns.> > Thanks, > > - Jason > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > 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.