[R] Basic vector operations was: Function to approximate complex integral
Marc Schwartz (via MN)
mschwartz at mn.rr.com
Wed Apr 19 21:46:15 CEST 2006
On Wed, 2006-04-19 at 15:25 -0400, Doran, Harold wrote:
> Dear List
>
> I apologize for the multiple postings. After being in the weeds on this
> problem for a while I think my original post may have been a little
> cryptic. I think I can be clearer. Essentially, I need the following
>
> a <- c(2,3)
> b <- c(4,5,6)
>
> (2*4) + (2*5) + (2*6) + (3*4) + (3*5) +(3*6)
>
> But I do not know of a built in function that would do this. Any
> suggestions?
<SNIP>
Unless I am missing something, how about:
> sum(a %x% b)
[1] 75
See ?"%x%"
You could also use outer():
> sum(outer(a, b, "*"))
[1] 75
See ?outer
HTH,
Marc Schwartz
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