Re: [R] Is there a better way than x[1:length(x)-1] ?

From: Petr Pikal <petr.pikal_at_precheza.cz>
Date: Thu 10 Aug 2006 - 20:01:29 EST


Hi

On 9 Aug 2006 at 17:30, John McHenry wrote:

Date sent:      	Wed, 9 Aug 2006 17:30:47 -0700 (PDT)
From:           	John McHenry <john_d_mchenry@yahoo.com>
To:             	r-help@stat.math.ethz.ch
Subject:        	[R] Is there a better way than x[1:length(x)-1] ?

> Hi WizaRds,
>
> In MATLAB you can do
>
> x=1:10
>
> and then specify
>
> x(2:end)
>
> to get
>
> 2 3 4 5 6 7 8 9 10
>
> or whatever (note that in MATLAB the parenthetic index notation is
> used, not brackets as in R). The point is that 'end' allows you to
> refer to the final index point of the array.
>
> Obviously there isn't much gain in syntax when the variable name is x,
> but when it's something like
>
> hereIsABigVariableName(j:end-i)
>
> it makes things a lot more readable than
>
> hereIsABigVariableName(j:length(hereIsABigVariableName)-i)
>
> In R I could do:
>
> n<- length(hereIsABigVariableName)
> hereIsABigVariableName[j:n-i]
>
> but I'd like to use something like 'end', if it exists.

It probably does not exist (but in R you never know :-) and you can easily to construct it yourself

 x <- 1:10
 end <- function(x) length(x)
 x[2:end(x)]

 [1] 2 3 4 5 6 7 8 9 10
 >

HTH
Petr

>
> Am I missing something obvious in R that does what 'end' does in
> MATLAB?
>
> Thanks,
>
> Jack.
>
>
> ---------------------------------
>
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>
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Petr Pikal
petr.pikal@precheza.cz



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