[R] Logical "in" test

[David B. Thompson, Ph.D., P.E., D.WRE, CFM]

OK, this should be trivial but I'm not finding it. I want to compress  
the test,

if (i==7 | i==10 | i==30 | i==50) {}

into something like

if (i in c(7,10,30,50)) {}

so I can build a "excludes" vector

excludes <- c(7,10,30,50)

and test

if (i in excludes) {}

However, I'm not finding a clue on how to accomplish this, if it can  
be done. Would someone with more R experience lend a helping hand  
please? A reference (so I can continue learning) would also be  
appreciated.

Thanks...

-=d

David Thompson, Ph.D., P.E., D.WRE, CFM
Civil Engineer/Hydrologist