[R] multiple versions of function

[ivo welch]

hi david---can you give just a little more of an example?  the
function should work with call by order, call by name, and data frame
whose columns are the names.  /iaw


----
Ivo Welch (ivo.welch at gmail.com)


On Mon, Jan 7, 2013 at 4:25 PM, David Winsemius <dwinsemius at comcast.net> wrote:
>
> On Jan 7, 2013, at 3:57 PM, ivo welch wrote:
>
>> dear R experts:
>>
>> I want to define a function the calculates the black-scholes value.
>> it takes 5 named parameters, BS <- function(S,K,dt,rf,sigma) {} .
>> let's presume I want to be able to call this not only with my 5
>> numeric vectors BS( sigma=0.3, S=100, K=100, dt=1, rf=0.1 ) and BS(
>> 100, 100, 1, 0.1, 0.3), but also with a data frame that contains the
>> variables alll in a neat data frame already, BS( data.frame( S=100,
>> K=100, dt=1, rf=0.1, sigma=0.3 )).  I could of course define BS6 and
>> BS1, but it would be nice to wrap this functionality into one function
>> that can do both.
>>
>> I know that BS has to parse an '...' argument, but there could be a
>> couple of magical R functions that might make this easier than I would
>> do it with my planned clunky version.     what's the elegant version?
>>
>
> apply( dfrm, 1, BS)
>
> --
>
> David Winsemius
> Alameda, CA, USA
>