From jeffrey.ryan at lemnica.com  Tue Feb 15 23:29:52 2011
From: jeffrey.ryan at lemnica.com (Jeffrey Ryan)
Date: Tue, 15 Feb 2011 16:29:52 -0600
Subject: [Rd] Request: Suggestions for "good teaching" packages,
 esp. with C code
In-Reply-To: <AANLkTikn+t2V22x4bv1hg+1B7_WE7y3aPfS+MFMFwwRy@mail.gmail.com>
References: <AANLkTikODppzk5=x7=TzVepH+aHuvaZUErf_0xQZ5ioX@mail.gmail.com>
	<4D5AF4A8.50001@auckland.ac.nz>
	<Pine.LNX.4.64.1102151353000.13921@cardinals.dreamhost.com>
	<AANLkTikn+t2V22x4bv1hg+1B7_WE7y3aPfS+MFMFwwRy@mail.gmail.com>
Message-ID: <AANLkTi=TUMLoimg179_i4vNNMesqeVLSLcSEPVjfCxSW@mail.gmail.com>

f3 <- function() {
  ( a <- 5 )
}

f4 <- function() {
  a <- 5
  a
}

On my machine f1,f2, and f4 all perform approx. the same.  The () in
f3 adds about 20% overhead.

Jeff

On Tue, Feb 15, 2011 at 4:22 PM, Kevin Wright <kw.stat at gmail.com> wrote:
> For those of you "familiar with R", here's a little quiz. ?What what's the
> difference between:
>
>
> f1 <- function(){
> ?a=5
> }
> f1()
>
> f2 <- function(){
> ?return(a=5)
> }
> f2()
>
>
> Kevin Wright
>
>
>
>
> On Tue, Feb 15, 2011 at 3:55 PM, Geoff Jentry <geoffjentry at hexdump.org>wrote:
>
>> On Wed, 16 Feb 2011, David Scott wrote:
>>
>>> 4. We don't want gratuitous use of "return" at the end of functions.
>>>> Why do people still do that?
>>>>
>>> Well I for one (and Jeff as well it seems) think it is good programming
>>> practice. It makes explicit what is being returned eliminating the
>>> possibility of mistakes and provides clarity for anyone reading the code.
>>>
>>
>> You're unnecessarily adding the overhead of a function call by explicitly
>> calling return().
>>
>> Sure it seems odd for someone coming from the C/C++/Java/etc world, but
>> anyone familiar with R should find code that doesn't have an explicit
>> return() call to be fully readable & clear.
>>
>> -J
>>
>>
>> ______________________________________________
>> R-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
>
> ? ? ? ?[[alternative HTML version deleted]]
>
> ______________________________________________
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> https://stat.ethz.ch/mailman/listinfo/r-devel
>



-- 
Jeffrey Ryan
jeffrey.ryan at lemnica.com

www.lemnica.com



[Rd] Request: Suggestions for "good teaching" packages, esp. with C code
Jeffrey Ryan