[R] Simple - Finding vector in a vector

[David L Carlson]

Building on Jessica and Steve's use of embed:

> X <- c(NA, 1, NA, 1, 1, 1, 1, 1, 1, NA, 1)
> Z <- rowSums(embed(X, 3))
> Z[is.na(Z)] <- 1
> Z
[1] 1 1 1 3 3 3 3 1 1

----------------------------------------------
David L Carlson
Associate Professor of Anthropology
Texas A&M University
College Station, TX 77843-4352

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Jessica Streicher
> Sent: Monday, October 08, 2012 9:19 AM
> To: Mike Spam
> Cc: r-help at r-project.org
> Subject: Re: [R] Simple - Finding vector in a vector
> 
> > x<-c(NA , 1 ,NA,  1 , 1 , 1 , 1 , 1  ,1 ,NA , 1)
> > embed(x,3)
>       [,1] [,2] [,3]
>  [1,]   NA    1   NA
>  [2,]    1   NA    1
>  [3,]    1    1   NA
>  [4,]    1    1    1
>  [5,]    1    1    1
>  [6,]    1    1    1
>  [7,]    1    1    1
>  [8,]   NA    1    1
>  [9,]    1   NA    1
> 
> > which(rowSums(embed(x,3))==3)
> [1] 4 5 6 7
> 
> gives you the first of the 3
> 
> On 08.10.2012, at 15:38, Mike Spam wrote:
> 
> > Sorry, i just realized, that it output the sum of all vectors. I can
> > work with this function but it would be much faster and easier if it
> > would be possible to get the positions of evry match.
> >
> > example:
> >
> > NA  1 NA  1  1  1  1  1  1 NA  1
> >
> > rle returns
> > lengths: int [1:6] 1 1 1 6 1 1
> >
> > what i need would be something like,
> > 1 1 1 3 3 3 3 1 1
> >
> > but anyway i can work with rle, if there is no suitable function.
> >
> > thanks,
> > Nico
> >
> >
> >
> > 2012/10/8 Mike Spam <ichmagspam at googlemail.com>:
> >> Hey Rui,
> >>
> >> Perfect! Thanks!! :)
> >>
> >> Nico
> >>
> >> 2012/10/8 Rui Barradas <ruipbarradas at sapo.pt>:
> >>> Hello,
> >>>
> >>> See ?rle
> >>>
> >>> Hope this helps,
> >>>
> >>> Rui Barradas
> >>> Em 08-10-2012 13:55, Mike Spam escreveu:
> >>>>
> >>>> Hi,
> >>>>
> >>>> just a simple question.
> >>>> Assumed i have a vector,
> >>>>
> >>>> FALSE  TRUE  TRUE  TRUE FALSE  TRUE FALSE  TRUE FALSE
> >>>> or
> >>>> NA  1  1  1 NA  1 NA  1 NA
> >>>>
> >>>> what i need is the position where an element is the same - three
> (or
> >>>> in general multiple) times in a row.
> >>>>
> >>>> in this case: i want to get the position where it is TRUE TRUE
> TRUE or 1 1
> >>>> 1
> >>>> it doesn't matter if it is the first, middle or last element. So
> the
> >>>> output could be 2 or 3 or 4
> >>>>
> >>>> My idea would be to lag the vector and calc differences... but i
> would
> >>>> prefer any build in (or time saving) function. :)
> >>>>
> >>>> thanks,
> >>>>
> >>>> Nico
> >>>>
> >>>> ______________________________________________
> >>>> 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.
> 
> ______________________________________________
> 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.