[R] like apply(x,1,sum), but using multiplication?

[Sundar Dorai-Raj]

Jose Quesada said the following on 5/7/2007 11:25 AM:
> Hi,
> 
> I need to multiply all columns in a matrix so something like  
> apply(x,2,sum), but using multiplication should do.
> I have tried apply(x,2,"*")
> I know this must be trivial, but I get:
> Error in FUN(newX[, i], ...) : invalid unary operator
> 
> The help for apply states that unary operators must be quoted. I tried  
> single quotes too, with the same results.
> 
> Thanks,
> -Jose
> 

Try: apply(x,2,prod)

HTH,

--sundar