[R] Interleaving elements of two vectors?

[bogdan romocea]

For a general solution without warnings try
interleave <- function(v1,v2)
{
ord1 <- 2*(1:length(v1))-1
ord2 <- 2*(1:length(v2))
c(v1,v2)[order(c(ord1,ord2))]
}
interleave(rep(1,5),rep(3,8))


> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Gabor
> Grothendieck
> Sent: Monday, March 06, 2006 12:12 AM
> To: Ajay Narottam Shah
> Cc: R-help
> Subject: Re: [R] Interleaving elements of two vectors?
>
> Try this (note that  your x and y do not have the same length
> and in this case the expression will recycle the shorter one
> and give a warning):
>
> z <- c(rbind(x, y))
>
>
> On 3/5/06, Ajay Narottam Shah <ajayshah at mayin.org> wrote:
> > Suppose one has
> >
> >        x <- c(1,  2,  7,  9,  14)
> >        y <- c(71, 72, 77)
> >
> > How would one write an R function which alternates between
> elements of
> > one vector and the next? In other words, one wants
> >
> >        z <- c(x[1], y[1], x[2], y[2], x[3], y[3], x[4],
> y[4], x[5], y[5])
> >
> > I couldn't think of a clever and general way to write this.
> I am aware
> > of gdata::interleave() but it deals with interleaving rows of a data
> > frame, not elems of vectors.
> >
> > --
> > Ajay Shah
> http://www.mayin.org/ajayshah
> > ajayshah at mayin.org
> http://ajayshahblog.blogspot.com
> > <*(:-? - wizard who doesn't know the answer.
> >
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