# Re: [R] problem of subscript value from vector and list

From: John Kane <jrkrideau_at_yahoo.ca>
Date: Thu, 28 Feb 2008 10:47:24 -0500 (EST)

I think you are getting a rounding or truncating problem in the printing

Try print[lon[x])

and see what you get
--- Jingru Dai <jingru.dai_at_sci.monash.edu.au> wrote:

> Hi, everyone
>
> I got some problems when trying to subscript the
> value of vector and
> list, by using calculated indices.
> Here is the vector I am generated
> lon<-rep(0,886);lat<-rep(0,691)
> for (i in 1:886){
> lon[i]<-112+0.05*(i-1)
> }
> for (i in 691:1){
> lat[i]<--44.5+0.05*(691-i)
> }
> For a given location of lon(xp) and lat(yp), I would
> like to calculate
> the position of them, and using that to get the
> value for the location
> from one list.
> xp<-c(112,112.05); yp<-c(-10,-10.10)
>
> x<-rep(0,length(xp)); y<-rep(0,length(yp))
> for (i in 1:length(xp)){
> x[i]<-(xp[i]-112)/0.05+1
> }
> for(j in 1:length(yp)){
> y[j]<-(-10-yp[j])/0.05+1
> }
> So here the value of x and y should indicate the
> position where xp and
> yp are in the vector lon and lat. And it appears to
> be the right
> number. But when I tried to retrieve the value of
> lon using the
> position, it returns the wrong value. Here's the
> result I got
> > x
> [1] 1 2
> > lon[x]
> [1] 112 112
> > lon[c(1,2)]
> [1] 112.00 112.05
> > y
> [1] 1 3
> > lat[y]
> [1] -10.00 -10.05
> > lat[c(1,3)]
> [1] -10.0 -10.1
>
> I have no idea why it returns the wrong value when I
> subscripts by x,
> while it works perfectly fine when I subscripts with
> the value of x
> directly. Is there any special rule of subscripts?
> My version of R is
> 2.5.1.
> Thanks a lot
>
> Jingru Dai
> ----
> School of Mathematical Sciences
> Rm 454, Building 28
> Monash University, 3800
> Victoria, Australia
>
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> and provide commented, minimal, self-contained,
> reproducible code.
>

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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. Received on Thu 28 Feb 2008 - 15:51:05 GMT

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