[R] Window on a vector

[R. Michael Weylandt]

It's not always true that going out of bounds in subscripting gives an
error (as you seem to assert in your original post)

x <- 1:3
x[4] # No error

and note that mean() has a na.rm argument.

Perhaps you should construct a *reproducible* example of what you
think will go wrong.

Michael

On Mon, Mar 12, 2012 at 11:22 AM, Alaios <alaios at yahoo.com> wrote:
> Yep I did some mistake while I was typing the example
> What I want is this one
> cbind(2^(0:(n-1))) and  the problem is that at the last "window" this is going to explode are there will be less elements than what the window asks for.
>
> How should I deal with that?
> Regards
> Alex
>
>
>
> ________________________________
>  From: David Winsemius <dwinsemius at comcast.net>
>
> Cc: R help <R-help at r-project.org>
> Sent: Saturday, March 10, 2012 2:49 PM
> Subject: Re: [R] Window on a vector
>
>
> On Mar 10, 2012, at 7:44 AM, Alaios wrote:
>
>> Dear all,
>> I have a large vector (lets call it myVector) and I want to plot its value with the logic below
>>
>> yaxis<-myVector[1]
>> yaxis<-c(xaxis,mean(myvector[2:3])
>> yaxis<-c(xaxis,mean(myvector[4:8])
>> yaxis<c(xaxis,mean(myvector[9:16])
>> yaxis<c(xaxis,mean(myvector[17:32])
>>
>> this has to stop when the new ..... yaxis<c(xaxis,mean(myvector[1024:2048]) will not find the correspondent number of elements, either wise it will stop with an error.

This doesn't seem true:

x <- 1:3

x[4] # Not an error

>>
>>
>> How I can do something like that in R?
>
> This will generate two series that are somewhat like your index specification. I say "somewhat" because you appear to have changed the indexing strategy in the middle. You start with 2^0. 2^1 and 2^2 as you "begin" but then switch to 2^3+1, and 2^4+1.
>
> n=20
> cbind(2^(0:(n-1)), 2^(1:n)-1)
>
> You can decide what to use for n with logic like:
>
> which.max(20 >= 2^(1:10) )
>
> Then you can use sapply or mapply.
>
>
>> Alex
>>     [[alternative HTML version deleted]]
>
> Please learn to post in plain text.
>
> --
> David Winsemius, MD
> West Hartford, CT
>        [[alternative HTML version deleted]]
>
>
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