# set functions

**Peter Dalgaard BSA
**
p.dalgaard@biostat.ku.dk

*04 Jan 2000 17:16:48 +0100*

Jonathan Rougier <J.C.Rougier@durham.ac.uk> writes:
>* I wonder if we might also include an "equiv" function along with the other
*>* set functions (ie "union", "intersect", etc), perhaps along the lines of
*>*
*>* "equiv" <- function(x, y) all(c(match(x, y, 0)>0, match(y, x, 0)>0))
*>*
*>* (which I think might be the quickest implementation). I use this type of
*>* function quite frequently: is there some reason why it is not in the base?
*
length(setdiff(x,y))==0 appears to be about twice as fast....
--
O__ ---- Peter Dalgaard Blegdamsvej 3
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk) FAX: (+45) 35327907
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