From simon.urbanek at r-project.org  Sun Jun 12 21:32:02 2005
From: simon.urbanek at r-project.org (Simon Urbanek)
Date: Sun, 12 Jun 2005 15:32:02 -0400
Subject: [Rd] by should use match.fun
In-Reply-To: <971536df050612122118e55e2f@mail.gmail.com>
References: <39B6DDB9048D0F4DAD42CB26AAFF0AFA64E98E@usctmx1106.merck.com>
	<971536df050612122118e55e2f@mail.gmail.com>
Message-ID: <71D65BAB-A619-4F24-8EBA-DAA15B4ADCD2@r-project.org>

On Jun 12, 2005, at 3:21 PM, Gabor Grothendieck wrote:

> On 6/12/05, Liaw, Andy <andy_liaw at merck.com> wrote:
>
>> I don't get the point.  ?by says:
>>
>
> The point is that all other functions of this sort including apply,  
> sapply,
> tapply, lapply work like that so 'by' ought to as well.
>
> Here is the example (changed to use iris) where I noticed it.   
> Suppose we
> want to create a list of rows:
>
> by(iris, row.names(iris), "(")

Umm.. why don't you just use

by(iris, row.names(iris), `(`)

In general I consider passing functions as text unnecessary - the  
only use I could think of is constructing function names from strings/ 
data and I'm not sure that is a good idea, either (it causes quite  
some performance issues) ... just my 2 pennies ...

Cheers,
Simon



[Rd] by should use match.fun
Simon Urbanek