[Rd] proposed change to 'sample'

[Peter Dalgaard]

William Dunlap wrote:
>> -----Original Message-----
>> From: r-devel-bounces at r-project.org 
>> [mailto:r-devel-bounces at r-project.org] On Behalf Of Patrick Burns
....
>>
>> I propose adding an argument that allows
>> the user (programmer) to avoid that
>> ambiguity:
>>
>> function (x, size, replace = FALSE, prob = NULL,
>>      max = length(x) == 1L && is.numeric(x) && x >= 1)
> 
> S+'s sample() has an argument 'n' to achieve
> the same result.  It has been there since at
> least 2005 (S+ 7.0.6).  sample(n=n) means to
> return a sample from seq_along(n), where n must
> be a scalar nonnegative integer.  sample(x=x)
> retains it old ambiguous meaning.
>   sample(x, size = n, replace = F, prob = NULL, n = NULL, ...)

Hmm, that doesn't really solve the issue does it? I.e., you still cannot
conveniently sample from a vector that is possibly of size 1.

I would be more inclined to make sampling from a vector the normal case,
and default x to say 1:max(n, size), forcing users to say sample(n=5) if
sampling from x=1:5 is desired. This could be a manageable change; the
deprecation sequence is a bit painful to think through, though.

-- 
Peter Dalgaard
Center for Statistics, Copenhagen Business School
Phone: (+45)38153501
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com