[R] intersect of list elements
Georg Otto
georg.otto at tuebingen.mpg.de
Fri Jul 21 19:39:09 CEST 2006
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
More information about the R-help
mailing list