Hi Jason,

try using comma's instead of colons. eg a[[c(1,6)]], a[[c(3,6)]] etc...

If you use a[[1:3]] this is equivalent to a[[c(1,2,3)]]. As the list only
contains 2 levels, this will give an error or NULL , depending on your R
version.

More info you find by ?"[["

Cheers
Joris


On Tue, Mar 30, 2010 at 5:47 PM, Dgnn <sharkbrainpdx@gmail.com> wrote:

>
> I have what may be a simple/foolish question, but I've done the due
> diligence
> and looked through pages of posts here as well as several of the PDFs on
> the
> CRAN site, but haven't been able find what I'm after.
>
> I am working with a list of say 3 histogram objects A, B & C, and each
> histogram is a list of 7 elements. I would like to access $name, the 6th
> element, of histograms A,B and C.
>
>
> Trial and error yielded some results that told me I clearly don't
> understand
> how R interprets index commands. For the histogram list above:
> a[1:2] give histograms A and B as expected.
> a[[1:2]] gives the second element of histogram 1, but a[[1:1]] gives all
> elements of histogram 1, while a[[1:3]] gives null?!
>
> If anyone could help with an explanation of indexing rules, or a source
> that
> does so, I would very much appreciate it. Oh and an answer to the first
> question!
>
> Thanks All
>
> Jason
>
>
> --
> View this message in context:
> http://n4.nabble.com/list-index-rules-evaluation-behavior-tp1745398p1745398.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help@r-project.org mailing list
> 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.
>



-- 
Joris Meys
Statistical Consultant

Ghent University
Faculty of Bioscience Engineering
Department of Applied mathematics, biometrics and process control

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