[R] Romoving elements from a vector. Looking for the opposite of c(), New user

[Gabor Grothendieck]

And here is a slightly shorter variation that encodes the
sequence number as the last two digits and then
removes it at the end:

xx <- 100 * x + seq(x) - match(x, x)
zz <- 100 * z + seq(z) - match(z, z)
setdiff(xx, zz) %/% 100


On Nov 15, 2007 4:54 PM, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
> Try this.  xx and zz are the same as x and z except
> they have a sequence number appended.  We then do
> a setdiff and remove the sequence numbers.
>
> > xx <- paste(x, seq(x) - match(x, x))
> > zz <- paste(z, seq(z) - match(z, z))
> > dd <- setdiff(xx, zz)
> > as.numeric(sub(" .*", "", dd))
> [1] 3 4 4 6 7 8 8 9
>
>
>
> On Nov 15, 2007 11:09 AM, Thomas Frööjd <tfrojd at gmail.com> wrote:
> > Not sure i explained it good enough. Ill try with an example
> >
> > say
> >
> > x=[3,3,4,4,4,4,5,5,6,8]
> > z=[3,4,4,5,5]
> >
> > what i want to get after removing z from x is something like
> > x=[3,4,4,6,8]
> >
> >
> > On Nov 15, 2007 3:29 PM, Charilaos Skiadas <cskiadas at gmail.com> wrote:
> > >
> > >
> > > On Nov 15, 2007, at 9:15 AM, Thomas Frööjd wrote:
> > >
> > > > Hi
> > > >
> > > > I have three vectors say x, y, z. One of them, x contains observations
> > > > on a variable. To x I want to append all observations from y and
> > > > remove all from z. For appending c() is easily used
> > > >
> > > > x <- c(x,y)
> > > >
> > > > But how do I remove all observations in z from x? You can say I am
> > > > looking for the opposite of c().
> > >
> > > If you are looking for the opposite of c, provided you want to remove
> > > the first part of things, then perhaps this would work:
> > >
> > > z<-c(x,y)
> > > z[-(1:length(x))]
> > >
> > > However, if you wanted to remove all appearances of elements of x
> > > from c(x,y), regardless of whether those elements appear in the x
> > > part of in the y part, I think you would want:
> > >
> > > z[!z %in% x]
> > >
> > > Probably there are other ways.
> > >
> > > Welcome to R!
> > >
> > > > Best regards
> > >
> > > Haris Skiadas
> > > Department of Mathematics and Computer Science
> > > Hanover College
> > >
> > > ______________________________________________
> > > R-help at r-project.org 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.
> > >
> >
> > ______________________________________________
> > R-help at r-project.org 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.
> >
>