[R] fast code

[Pantelis Andreou]

Hello Reid,
thank you for the suggestion.
Regards,
Pantelis

> x1<-c(3,4,6.5,20,35)
> x2<-c(3.1,4.2,5,24,38)
> i <- cut(x2,c(x1,Inf),labels=FALSE)
> i
[1] 1 2 2 4 5
> x3 <- x1[i]
> x3
[1]  3  4  4 20 35
> 


On Fri, 6 Dec 2002, Huntsinger, Reid wrote:

> You could use "cut" as follows:
> 
> i <- cut(x2,c(x1,Inf),labels=FALSE)
> 
> to get the intervals of x1 into which the
> entries of x2 fall, then
> 
> x3 <- x1[i]
> 
> to get the left endpoints. This will give NA for elements of
> x2 smaller than any element of x1, which I think you want. 
> You may want to play with the options to "cut" to get the
> right behavior for exact equality between elements of x1 and x2.
> 
> Note x2 need not be sorted. I don't see a way to take advantage
> of sorted x2 without explicit looping.
> 
> Reid Huntsinger
> 
> 
> 
> -----Original Message-----
> From: Pantelis Andreou [mailto:pan at mathstat.dal.ca]
> Sent: Friday, December 06, 2002 1:21 PM
> To: Janusz Kawczak
> Cc: r-help at stat.math.ethz.ch
> Subject: Re: [R] fast code
> 
> 
> Hello again,
> here is an example
> x1      x2      x3
> 3       3.1     3
> 4       4.2     4
> 6.5     5	4
> 20      24	20
> 35      38	35
> 
> 
> On Fri, 6 Dec 2002, Janusz Kawczak wrote:
> 
> > Example would help!
> > 
> > On Fri, 6 Dec 2002, Pantelis Andreou wrote:
> > 
> > > Date: Fri, 6 Dec 2002 14:09:22 -0400 (AST)
> > > From: Pantelis Andreou <pan at mathstat.dal.ca>
> > > To: r-help at stat.math.ethz.ch
> > > Subject: [R] fast code
> > >
> > > Hello again,
> > > I think I made a mistake discribing the problem.
> > > I have two column vectors x1 and x2 both in increasing order.
> > > I need a column vector x3 such that
> > > the jth entry of x3 is the maximum ith entry x1 which is smaller
> > > than the jth entry of x2.
> > > Regards,
> > > Pantelis
> > >
> > > ______________________________________________
> > > R-help at stat.math.ethz.ch mailing list
> > > http://www.stat.math.ethz.ch/mailman/listinfo/r-help
> > >
> > 
> >
> 
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