[R] Predict polynomial problem

[Thomas Lumley]

On Tue, 19 Jan 2010, Barry Rowlingson wrote:

> On Tue, Jan 19, 2010 at 5:37 PM, Charles C. Berry <cberry at tajo.ucsd.edu>wrote:
>
>>
>>> Note:
>>>
>>>   i <- 20
>>>>  bquote(y ~ poly(x,.(i)))
>>>>
>>> y ~ poly(x, 20)
>>>
>>>
> I see it now. bquote(y~poly(x,.(i))) gets it's 'i' there and then, sticks
> it in the returned expression as the value '20', so any further evaluations
> get poly(x,20). This is reminiscent of the way macro languages work...

Yes, bquote() was written to mimic the backquote macro in Lisp, hence its name.

      -thomas

Thomas Lumley			Assoc. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle