[R] intersect of list elements
Berton Gunter
gunter.berton at gene.com
Fri Jul 21 19:55:00 CEST 2006
FAQ 7.21.
But there are perhaps slicker ways.
-- Bert Gunter
Genentech Non-Clinical Statistics
South San Francisco, CA
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Georg Otto
> Sent: Friday, July 21, 2006 10:39 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] intersect of list elements
>
>
> Hi,
>
> i have a list of several vectors, for example:
>
> > vectorlist
> $vector.a.1
> [1] "a" "b" "c"
>
> $vector.a.2
> [1] "a" "b" "d"
>
> $vector.b.1
> [1] "e" "f" "g"
>
>
> I can use intersect to find elements that appear in $vector.a.1 and
> $vector.a.2:
>
> > intersect(vectorlist[[1]], vectorlist[[2]])
> [1] "a" "b"
>
>
> I would like to use grep to get the vectors by their names matching an
> expression and to find the intersects between those vectors. For the
> first step:
>
> > vectorlist[grep ("vector.a", names(vectorlist))]
> $vector.a.1
> [1] "a" "b" "c"
>
> $vector.a.2
> [1] "a" "b" "d"
>
>
> Unfortunately, I can not pass the two vectors as argument to
> intersect:
>
> > intersect(vectorlist[grep ("vector.a", names(vectorlist))])
> Error in unique(y[match(x, y, 0)]) : argument "y" is missing,
> with no default
>
> I am running R Version 2.3.1 (2006-06-01)
>
>
> Could somone help me to solve this?
>
> Cheers,
>
> Georg
>
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