[R] combining lists of pairs

[Charles C. Berry]

On Thu, 17 Jul 2008, olvrmrs at aol.com wrote:

> Hi everybody,
>
> This has been causing me some trouble:
>
> I want to combine several lists of pairs into a single?vector but keep the pairs together. The lists are of the form:
> (1)?x1 x2 x3... N?
> (2) y1 y2 y3..? N
>
> I would like to keep it this way, simply appending one list to another, e.g.
> (1) x1i x2i... x1j x2j... N
> (2) etc.
>
> A?method like c(...) does not achieve this. It creates a single list, disregarding the pairs.

Then you do not literally have a list of pairs.

You need to do this when posting:

> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

Note:

> lp <- list(c(1,2),c(3,4),c(5,6))
> lp2 <- list(c(1,2),c(3,4),c(5,6))
> c(lp,lp2) # HA! A list of all pairs.

So c(...) works on a list of pairs.

=====

If what you have is a pair of vectors of atomic elements stored as a list, 
you can use rbind( as.data.frame(list1), as.data.frame(list2) , ... )

If not, I might suggest you either convert your structure to a list of 
pairs, or a data.frame, and use the one of the above approaches.

Or tell us what your object really is so we might better advise.

Hint see:

 	?str

and use it before replying.

HTH,

Chuck


>
> Is there a more efficient way of doing it?
>
> Thanks!
> Oliver Marshall
>
> 	[[alternative HTML version deleted]]
>
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>

Charles C. Berry                            (858) 534-2098
                                             Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu	            UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901