[Rd] Inefficiency in df$col

[Duncan Murdoch]

On 04/02/2019 10:48 a.m., peter dalgaard wrote:
> 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.

Since $.data.frame is in the base package, it is handled specially in 
src/library/base/R/zzz.R.  I'll email you a patch if it compiles and 
passes checks.

Duncan Murdoch
> 
> -pd
> 
>> On 4 Feb 2019, at 15:32 , Duncan Murdoch <murdoch.duncan using 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
>>
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>