On 1/31/2006 4:55 PM, Gabor Grothendieck wrote: > I think that a pointer to ?formula needs to be added to ?":"
Good suggestion; I'll do it. Duncan Murdoch > > > On 1/31/06, Liaw, Andy <[EMAIL PROTECTED]> wrote: >> ":" in a formula is not the same as ":" otherwise! >> >> Andy >> >> From: Ionut Florescu >>> a:b means - all the element in the vector from a to b >>> a[,-1] means for the matrix a keep all the rows but not the last or >>> first -can't remember column. >>> When in doubt do what I do make a small matrix and apply the >>> command see >>> what it does. >>> After this: >>> > a=matrix(c(1:9),3,3) >>> > a[,-1] >>> [,1] [,2] >>> [1,] 4 7 >>> [2,] 5 8 >>> [3,] 6 9 >>> >>> you see that -1 eliminates the first column. >>> I found the R manual useless myself. >>> The only thing useful is the search function in the html >>> help. That has >>> examples. >>> >>> Ionut Florescu >>> >>> Michael wrote: >>>> Hi all, >>>> >>>> R is so difficult. I am so desperate. >>>> >>>> What does the ":" mean in the following statement? >>>> >>>> What does the "[, -1]" mean? >>>> >>>> >>>>> # Leaps takes a design matrix as argument: throw away the intercept >>>>> # column or leaps will complain >>>>> >>>>> X <- model.matrix(lm(V ~ I + D + W +G:I + P + N, >>> election.table))[,-1] >>>> Thanks a lot! >>>> >>>> [[alternative HTML version deleted]] >>>> >>>> ______________________________________________ >>>> 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 >>>> >>> ______________________________________________ >>> 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 >>> >>> >> ______________________________________________ >> 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 >> > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
