> On 26 Jun 2017, at 19:04 , Martin Maechler <maech...@stat.math.ethz.ch> wrote:
>
>>>>>> peter dalgaard <pda...@gmail.com>
>>>>>> on Mon, 26 Jun 2017 13:43:28 +0200 writes:
>
>> This seems to be due to changes made by Martin Maechler in
>> 2008. Presumably this fixed something, but it escapes my
>> memory.
>
> Yes: The change set (svn -c46441) also contains the following NEWS entry
>
> BUG FIXES
>
> o within(<dataframe>, { ... }) now also works when '...' removes
> more than one column.
>
The odd thing is that the assign-NULL technique used for removing a single
column, NOW also seems to work for several columns in a data frame, so I wonder
what the bug was back then...
-pd
>
>> However, it seems to have broken the equivalence
>> between within.list and within.data.frame, so now
>
>> within.list <- within.data.frame
>
>> does not suffice.
>
> There have been many improvements since then, so maybe we can
> change the code so that the above will work again.
>
> Another problem seems that we had no tests of within.list()
> anywhere... so we will have them now.
>
> I've hade an idea that seems to work and even simplify the
> code.... will get back to the issue later in the evening.
>
> Martin
>
>
>> The crux of the matter seems to be that both the following
>> constructions work for data frames
>
>>> aq <- head(airquality)
>>> names(aq)
>> [1] "Ozone" "Solar.R" "Wind" "Temp" "Month" "Day"
>>> aq[c("Wind","Temp")] <- NULL
>>> aq
>> Ozone Solar.R Month Day
>> 1 41 190 5 1
>> 2 36 118 5 2
>> 3 12 149 5 3
>> 4 18 313 5 4
>> 5 NA NA 5 5
>> 6 28 NA 5 6
>>> aq <- head(airquality)
>>> aq[c("Wind","Temp")] <- vector("list",2)
>>> aq
>> Ozone Solar.R Month Day
>> 1 41 190 5 1
>> 2 36 118 5 2
>> 3 12 149 5 3
>> 4 18 313 5 4
>> 5 NA NA 5 5
>> 6 28 NA 5 6
>
>> However, for lists they differ:
>
>>> aq <- as.list(head(airquality))
>>> aq[c("Wind","Temp")] <- vector("list",2)
>>> aq
>> $Ozone
>> [1] 41 36 12 18 NA 28
>
>> $Solar.R
>> [1] 190 118 149 313 NA NA
>
>> $Wind
>> NULL
>
>> $Temp
>> NULL
>
>> $Month
>> [1] 5 5 5 5 5 5
>
>> $Day
>> [1] 1 2 3 4 5 6
>
>>> aq <- as.list(head(airquality))
>>> aq[c("Wind","Temp")] <- NULL
>>> aq
>> $Ozone
>> [1] 41 36 12 18 NA 28
>
>> $Solar.R
>> [1] 190 118 149 313 NA NA
>
>> $Month
>> [1] 5 5 5 5 5 5
>
>> $Day
>> [1] 1 2 3 4 5 6
>
>
>> -pd
>
>>> On 26 Jun 2017, at 04:40 , Hong Ooi via R-devel <r-devel@r-project.org>
>>> wrote:
>>>
>>> The behaviour of within() with list input changes if you delete 2 or more
>>> variables, compared to deleting one:
>>>
>>> l <- list(x=1, y=2, z=3)
>>>
>>> within(l,
>>> {
>>> rm(z)
>>> })
>>> #$x
>>> #[1] 1
>>> #
>>> #$y
>>> #[1] 2
>>>
>>>
>>> within(l, {
>>> rm(y)
>>> rm(z)
>>> })
>>> #$x
>>> #[1] 1
>>> #
>>> #$y
>>> #NULL
>>> #
>>> #$z
>>> #NULL
>>>
>>>
>>> When 2 or more variables are deleted, the list entries are instead set to
>>> NULL. Is this intended?
>>>
>>> ______________________________________________
>>> R-devel@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....@cbs.dk Priv: pda...@gmail.com
>
>
>
>
>
>
>
>
--
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: pd....@cbs.dk Priv: pda...@gmail.com
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