R help - Sep 2016 - dplyr or plyr or both?

The incorrect results are unfortunate and can trip up the inexperienced user,
but this problem is straightforward to resolve if you explicitly specify which
versions of the conflicting functions to use. The more interesting question I
saw was whether the intent is to deprecate plyr, but so far that  does not
appear to be the case.

While I agree that mixing them can be trouble-prone, I think in many cases both
will continue to be used.
-- 
Sent from my phone. Please excuse my brevity.

On September 15, 2016 10:08:05 AM PDT, Frans Marcelissen
<fransiepansiekevertje at gmail.com> wrote:
>Hello Christopher and others
>:
>What cannot be stressed enough is: do not combine both packages, it
>gives
>errors and incorrect results! I will show that below
>--------------------------------------------------------
>a<-data.frame(groep=1:4,v=1:40)
>library(dplyr)
>a %>% group_by(groep) %>% summarise(m=mean(v),n=n())
># groep     m     n
># <int> <dbl> <int>
># 1     1    19    10
># 2     2    20    10
># 3     3    21    10
># 4     4    22    10
># correct
>
>library(plyr)
>a %>% group_by(groep) %>% summarise(m=mean(v),n=n())
>
>Error in n() : This function should not be called directly
># ???
>a %>% group_by(groep) %>% summarise(m=mean(v))
># m
># 1 20.5
>#incorrect!
>--------------------------------------------------
>
>So both n() and group_by from dplyr don't work after library(plyr)!
>
>My advice is: do not use plyr. Unfortunately plyr has some functions
>that
>are very important, and that are not in dplyr. For instance:
>rbind.fill()
>(for combining the rows of two dataframes with unequal columns). If you
>need this: do'nt library plyr, use plyr::rbind.fil
>
>Until now I have the impression that it is also possible to library
>dplyr
>after plyr, but it is better to remove plyr!
>
>This is a serious problem that has been reported before, but not solved
>(in
>dplyr 0.5.0 and plyr 1.8.4)
>
>Frams
>
>2016-09-15 16:09 GMT+02:00 Christopher W Ryan <cryan at
binghamton.edu>:
>
>> I've set myself the task of learning about these packages, and
about
>> tidy data concepts.
>>
>> What is the relationship between plyr and dplyr?  Does the latter
>> replace the former (meaning I can concentrate on learning the
>latter)?
>> Or is there ever a need to use functions from both (meaning I should
>> learn both)?
>>
>> Thanks.
>>
>> --Chris Ryan
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/
>> posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>	[[alternative HTML version deleted]]
>
>______________________________________________
>R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.

I never realised that nonsense results don?n bother experienced users?..
Probably I am not experienced wiith my 6years of R professional work.
I think your advise is incomplete: a %>% dplyr::group_by(groep) %>%
dplyr::summarise(m=mean(v),n=dplyr::n())
Gives the same problems and makes the line ugly. Or how would you do this?
I stick with my advise: use dplyr. if you do not need plyr: stay away from it.
If you need it: do not attach it, but use the plyr:: notation.
I agree that plyr is something else as dplyr, and unfortunately plyr will be
used for some time.

Verzonden vanuit Mail voor Windows 10

Van: Jeff Newmiller
	[[alternative HTML version deleted]]

You are ignoring the warning issued when you load plyr after dplyr and then
complaining. Simply reversing the sequence of library statements is sufficient
to fix your example.

I agree that it is not ideal and that using just one at a time is easier, but
you can use both, and for now a lot of packages use plyr and are not going to be
rewritten for dplyr because dplyr doesn't do everything plyr does.

The more subtle problem with using both is that you may need to be explicit
about which package's function to use with dplyr:: or plyr:: notation, so
WHERE POSSIBLE I also recommend using dplyr.
-- 
Sent from my phone. Please excuse my brevity.

On September 15, 2016 1:28:51 PM PDT, Frans Marcelissen
<fransiepansiekevertje at gmail.com> wrote:
>I never realised that nonsense results don?n bother experienced
>users?.. Probably I am not experienced wiith my 6years of R
>professional work.
>I think your advise is incomplete: a %>% dplyr::group_by(groep) %>%
>dplyr::summarise(m=mean(v),n=dplyr::n())
>Gives the same problems and makes the line ugly. Or how would you do
>this?
>I stick with my advise: use dplyr. if you do not need plyr: stay away
>from it. If you need it: do not attach it, but use the plyr:: notation.
>I agree that plyr is something else as dplyr, and unfortunately plyr
>will be used for some time.
>
>Verzonden vanuit Mail voor Windows 10
>
>Van: Jeff Newmiller