My purpose is to create chains of list objects if elements of the object
overlap. If there is no overlap the object remains as it is. My plan is to
identify snps that are in ld. The letters in each list object represent
snps that are in ld in respect to the first snp (or letter). The first snp
(or letter) is identical with names (list), respectively.
Yes, (@Bert) my example was wrong. But the function I posted is correct, I
hope. At least it does what I want for some sets I tested.

snp.block <- function (huz)
    {
        for (i in names (huz))
             {
                 chain1 <- huz[[i]]
                 for (k in names (huz))
                     {
                         chain2 <- huz[[k]]
                         if (k==i)
                             {

   next
                             }
                         else if (length (intersect (chain1, chain2))!=0)
                             {
                                 chain3 <- union (chain1, chain2)
                                 chain1 <- chain3
                                 huz[[i]] <- sort (chain3)
                             }
                         else if (length (intersect (chain1, chain2)) == 0)
                             {
                                 chain3 <- chain1
                                 huz[[i]] <- sort (chain3)
                                 next
                             }
                     }
             }
        huz <- unique (huz)
        return (huz)
    }



2013/11/10 Bert Gunter <gunter.berton@gene.com>

> Your specification is a unclear (to me anyway): What do you want to
> return if the intersection is empty? What if intersect(ja[[i]],
> ja[[i+1]]) is empty for all i? What if  length(intersect( ja[[i]],
> ja[[i+1]] )) ==0 but intersect(ja[[i]],ja[[i+2]]) is nonempty?  Your
> example isn't -- you did not specify what the return should be on your
> list.
>
> Note also that your example test  is wrong: the length of the
> intersection must =0 not the intersection.
>
> -- Bert
>
>
>
> On Sat, Nov 9, 2013 at 12:45 PM, Hermann Norpois <hnorpois@gmail.com>
> wrote:
> > Hello,
> >
> > I have a list called ja and I wish to unify list objects if there is some
> > overlap.
> > For instance something like
> >
> > if (length (intersect (ja[[1]], ja[[2]]) !=0) { union (ja[[1]], ja[[2]] }
> >
> > but of course it should work cumulatively (for larger data sets).
> >
> > Could you please give me a hint.
> >
> > Thanks
> > Hermann
> >
> >> ja
> > $A
> > [1] "A" "B" "F" "G" "H"
> >
> > $B
> > [1] "B" "F" "I"
> >
> > $C
> > [1] "C" "F" "I" "K"
> >
> > $D
> > [1] "D" "L" "M" "N"
> >
> > $L
> > [1] "L" "O" "P"
> >
> >
> > dput (ja)
> > structure(list(A = c("A", "B", "F", "G", "H"), B = c("B", "F",
> > "I"), C = c("C", "F", "I", "K"), D = c("D", "L", "M", "N"), L = c("L",
> > "O", "P")), .Names = c("A", "B", "C", "D", "L"))
> >
> >         [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > 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.
>
>
>
> --
>
> Bert Gunter
> Genentech Nonclinical Biostatistics
>
> (650) 467-7374
>

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