"I see: consistency with additive identity. "
Ummm, well:
> 1+NULL
numeric(0)
> sum(1,NULL)
[1] 1
Of course, there could well be something here I don't get, but that doesn't
look very consistent to me. However, as I said privately, so long as the
corner case behavior is documented, which it is, I don't care.
Cheers,
Bert
Bert Gunter
"The trouble with having an open mind is that people keep coming along and
sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
On Wed, Mar 21, 2018 at 10:26 AM, Boris Steipe <boris.ste...@utoronto.ca>
wrote:
> I see: consistency with additive identity. That makes sense. Thanks.
>
> B.
>
>
> > On Mar 21, 2018, at 1:22 PM, peter dalgaard <pda...@gmail.com> wrote:
> >
> > No. The empty sum is zero. Adding it to another sum should not change
> it. Nothing audacious about that. This is consistent; other definitions
> just cause trouble.
> >
> > -pd
> >
> >> On 21 Mar 2018, at 18:05 , Boris Steipe <boris.ste...@utoronto.ca>
> wrote:
> >>
> >> Surely the result of summation of non-existent values is not defined,
> is it not? And since the NA values have been _removed_, there's nothing
> left to sum over. In fact, pretending the the result in that case is zero
> would appear audacious, no?
> >>
> >> Cheers,
> >> Boris
> >>
> >>
> >>
> >>
> >>
> >>> On Mar 21, 2018, at 12:58 PM, Jeff Newmiller <jdnew...@dcn.davis.ca.us>
> wrote:
> >>>
> >>> What do you mean by "should not"?
> >>>
> >>> NULL means "missing object" in R. The result of the sum function is
> always expected to be numeric... so NA_real or NA_integer could make sense
> as possible return values. But you cannot compute on NULL so no, that
> doesn't work.
> >>>
> >>> See the note under the "Value" section of ?sum as to why zero is
> returned when all inputs are removed.
> >>> --
> >>> Sent from my phone. Please excuse my brevity.
> >>>
> >>> On March 21, 2018 9:03:29 AM PDT, Boris Steipe <
> boris.ste...@utoronto.ca> wrote:
> >>>> Should not the result be NULL if you have removed the NA with
> >>>> na.rm=TRUE ?
> >>>>
> >>>> B.
> >>>>
> >>>>
> >>>>
> >>>>> On Mar 21, 2018, at 11:44 AM, Stefano Sofia
> >>>> <stefano.so...@regione.marche.it> wrote:
> >>>>>
> >>>>> Dear list users,
> >>>>> let me ask you this trivial question. I worked on that for a long
> >>>> time, by now.
> >>>>> Suppose to have a data frame with NAs and to sum some columns with
> >>>> rowSums:
> >>>>>
> >>>>> df <- data.frame(A = runif(10), B = runif(10), C = rnorm(10))
> >>>>> df[1, ] <- NA
> >>>>> rowSums(df[ , which(names(df) %in% c("A","B"))], na.rm=T)
> >>>>>
> >>>>> If all the elements of the selected columns are NA, rowSums returns 0
> >>>> while I need NA.
> >>>>> Is there an easy and efficient way to use rowSums within a function
> >>>> like
> >>>>>
> >>>>> function(x) ifelse(all(is.na(x)), as.numeric(NA), rowSums...)?
> >>>>>
> >>>>> or an equivalent function?
> >>>>>
> >>>>> Thank you for your help
> >>>>> Stefano
> >>>>>
> >>>>>
> >>>>>
> >>>>> (oo)
> >>>>> --oOO--( )--OOo----------------
> >>>>> Stefano Sofia PhD
> >>>>> Area Meteorologica e Area nivologica - Centro Funzionale
> >>>>> Servizio Protezione Civile - Regione Marche
> >>>>> Via del Colle Ameno 5
> >>>>> 60126 Torrette di Ancona, Ancona
> >>>>> Uff: 071 806 7743
> >>>>> E-mail: stefano.so...@regione.marche.it
> >>>>> ---Oo---------oO----------------
> >>>>>
> >>>>> ________________________________
> >>>>>
> >>>>> AVVISO IMPORTANTE: Questo messaggio di posta elettronica può
> >>>> contenere informazioni confidenziali, pertanto è destinato solo a
> >>>> persone autorizzate alla ricezione. I messaggi di posta elettronica
> per
> >>>> i client di Regione Marche possono contenere informazioni
> confidenziali
> >>>> e con privilegi legali. Se non si è il destinatario specificato, non
> >>>> leggere, copiare, inoltrare o archiviare questo messaggio. Se si è
> >>>> ricevuto questo messaggio per errore, inoltrarlo al mittente ed
> >>>> eliminarlo completamente dal sistema del proprio computer. Ai sensi
> >>>> dell’art. 6 della DGR n. 1394/2008 si segnala che, in caso di
> necessità
> >>>> ed urgenza, la risposta al presente messaggio di posta elettronica può
> >>>> essere visionata da persone estranee al destinatario.
> >>>>> IMPORTANT NOTICE: This e-mail message is intended to be received only
> >>>> by persons entitled to receive the confidential information it may
> >>>> contain. E-mail messages to clients of Regione Marche may contain
> >>>> information that is confidential and legally privileged. Please do not
> >>>> read, copy, forward, or store this message unless you are an intended
> >>>> recipient of it. If you have received this message in error, please
> >>>> forward it to the sender and delete it completely from your computer
> >>>> system.
> >>>>>
> >>>>> --
> >>>>> Questo messaggio stato analizzato da Libra ESVA ed risultato non
> >>>> infetto.
> >>>>> This message was scanned by Libra ESVA and is believed to be clean.
> >>>>>
> >>>>>
> >>>>> [[alternative HTML version deleted]]
> >>>>>
> >>>>> ______________________________________________
> >>>>> R-help@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.
> >>>>
> >>>> ______________________________________________
> >>>> R-help@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.
> >>
> >> ______________________________________________
> >> R-help@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.
> >
> > --
> > 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
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
> ______________________________________________
> R-help@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@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.
