[R] Logical "and"

[Roger Bivand]

On Thu, 11 Nov 2004, Alexander Sokol wrote:

?setdiff

> setdiff(a,b)
[1]  1  5 11


> Hello,
> 
> I have the following very simple problem:
> 
> Say I have two vectors,
> 
> a<-c(1,7,4,5,9,11)
> b<-c(7,4,9)
> 
> I would like to create a vector containing the elements in a which are not in 
> b.
> 
> Obviously, this is possible by writing
> 
> a[a!=b[1] & a!=b[2] & a!=b[3]]
> 
> But I would like a solution which is applicable to the situation where the 
> number of elements in b is unknown.
> 
> I have looked in the R manuals, the FAQ and the mailing lists, but have been 
> unable to find a solution.
> 
> Thank you for your replies,
>  Alexander
> 
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-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand at nhh.no