From pd@|gd @end|ng |rom gm@||@com  Mon Feb  4 16:48:12 2019
From: pd@|gd @end|ng |rom gm@||@com (peter dalgaard)
Date: Mon, 4 Feb 2019 16:48:12 +0100
Subject: [Rd] Inefficiency in df$col
In-Reply-To: <881488b4-7225-1f0b-bde5-9ceed235533d@gmail.com>
References: <mailman.48126.3.1549278001.57232.r-devel@r-project.org>
 <20190204142013.GA10151@mail.cs.toronto.edu>
 <881488b4-7225-1f0b-bde5-9ceed235533d@gmail.com>
Message-ID: <45CEFFBB-DE6E-4CEC-A98E-F23E5427A4A8@gmail.com>

Does either of you have a patch against current R-devel? 

I tried the obvious, but the build dies with

building package 'tools'
all.R is unchanged
../../../../library/tools/libs/x86_64/tools.so is unchanged
installing 'sysdata.rda'
Error in get(method, envir = home) : object '$.data.frame' not found
Error: unable to load R code in package 'tools'
Execution halted

...and I can't really be arsed to dig into tools to see exactly where it is hardcoding the existence of $.data.frame.

-pd

> On 4 Feb 2019, at 15:32 , Duncan Murdoch <murdoch.duncan at gmail.com> wrote:
> 
> On 04/02/2019 9:20 a.m., Radford Neal wrote:
>>>> I think you might want to just delete the definition of $.data.frame,
>>>> reverting to the situation before R-3.1.0.
>>> 
>>> I imagine the cause is that the list version is done in C code rather
>>> than R code (i.e. there's no R function `$.list`).  So an alternative
>>> solution would be to also implement `$.data.frame` in the underlying C
>>> code.  This won't be quite as fast (it needs that test for NULL), but
>>> should be close in the full match case.
>> I maybe wasn't completely clear.  The $ operator for data frames was
>> previously done in C - since it was done by the same primitive as for
>> lists.  In R-3.1.0, this was changed - producing a massive slowdown -
>> for the purpose of giving a warning on partial matches even if the
>> user had not set the warnPartialMatchDollar option to TRUE.  In
>> R-3.1.1, this was changed to not warn unless warnPartialMatchDollar was
>> TRUE which was the PREVIOUS behaviour.  In other words, this change
>> reverted the change made in R-3.1.0.  But instead of simply deleting
>> the definition of $.data.frame, R-3.1.1 added extra code to it, the
>> only effect of which is to slightly change the wording of the warning
>> message from what is produced for any other list, while still retaining
>> the massive slowdown.
>> There is no need for you to write $.data.frame in C.  You just need
>> to delete the version written in R.
> 
> Sorry, I did misunderstand.  Thanks for the clarification.
> 
> But if the "You" in your last sentence meant me, it needs to be "They": I am not a member of R Core and can't make any changes to the sources.
> 
> Duncan Murdoch
> 
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel

-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com



[Rd] Inefficiency in df$col
peter dalgaard