isolate elements in vector that match one of many possible values

x <- c(1,2,3,4)
y <- c(1,2,4)
match(y,x)

Hi all,

I want to get the index numbers of all elements of a vector which match any
of a long series of possible values.  Say x <- c(1,2,3,4) and I want to know
which values are equal to 1, 2 or 4.  I could do

which(x == 1 | x==2 | x==4)
[1] 1 2 4

This gets really ugly though, when the list of values of interest is really
long.  Is there a nicer way to do this?  Something akin to the MySQL
construction in(), as in

#MySQL script example
Select * from table where parameter in(x,y,z);

Thanks!

-- 
W. Andrew Barr
Biological Anthropology
University of Texas at Austin

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