Hello, I just realized that 1^NA outputs 1 while 1.1^NA outputs NA in R v3.3.1 and R v3.2.3. I tried other values such as 0^NA and 2^NA, and they all output NA. I don't understand this inconsistency here. Shouldn't 1^NA output NA as well? Why does R handle it differently? Or is this a bug in these particular versions of R? Thanks, Da [[alternative HTML version deleted]]
Dear Da, NA represents an unknown value x. 1 ^ x = 1 for all possible values of x. Hence 1 ^ NA = 1. Best regards, ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance Kliniekstraat 25 1070 Anderlecht Belgium To call in the statistician after the experiment is done may be no more than asking him to perform a post-mortem examination: he may be able to say what the experiment died of. ~ Sir Ronald Aylmer Fisher The plural of anecdote is not data. ~ Roger Brinner The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data. ~ John Tukey 2016-11-17 20:19 GMT+01:00 Da Zheng <zhengda1936 at gmail.com>:> Hello, > > I just realized that 1^NA outputs 1 while 1.1^NA outputs NA in R v3.3.1 and > R v3.2.3. > I tried other values such as 0^NA and 2^NA, and they all output NA. > I don't understand this inconsistency here. Shouldn't 1^NA output NA as > well? Why does R handle it differently? Or is this a bug in these > particular versions of R? > > Thanks, > Da > > [[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. >[[alternative HTML version deleted]]
On 17/11/2016 2:19 PM, Da Zheng wrote:> Hello, > > I just realized that 1^NA outputs 1 while 1.1^NA outputs NA in R v3.3.1 and > R v3.2.3. > I tried other values such as 0^NA and 2^NA, and they all output NA. > I don't understand this inconsistency here. Shouldn't 1^NA output NA as > well? Why does R handle it differently? Or is this a bug in these > particular versions of R?Our usual interpretation of NA is "an unknown value". So 1^NA would give NA if there were multiple possible values for it depending on what number you substitute for NA, and should give the unique answer if there's only one possibility (as for example NA | TRUE gives TRUE). As far as I can see, 1 raised to any power (even infinite ones) should give 1, so the answer looks fine to me. That's not true of any of the other bases you mention (just as NA | FALSE gives NA). Duncan Murdoch
On Nov 17, 2016 11:55 AM, "Thierry Onkelinx" <thierry.onkelinx at inbo.be> wrote:> > Dear Da, > > NA represents an unknown value x. 1 ^ x = 1 for all possible values of x. > Hence 1 ^ NA = 1. >That is false. For any n, n-1 of the nth roots of 1 differ from 1(they are complex). I don't have my computer with me. What does (1+ 0i)^ NA give? Bert> Best regards, > > ir. Thierry Onkelinx > Instituut voor natuur- en bosonderzoek / Research Institute for Nature and > Forest > team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance > Kliniekstraat 25 > 1070 Anderlecht > Belgium > > To call in the statistician after the experiment is done may be no more > than asking him to perform a post-mortem examination: he may be able tosay> what the experiment died of. ~ Sir Ronald Aylmer Fisher > The plural of anecdote is not data. ~ Roger Brinner > The combination of some data and an aching desire for an answer does not > ensure that a reasonable answer can be extracted from a given body ofdata.> ~ John Tukey > > 2016-11-17 20:19 GMT+01:00 Da Zheng <zhengda1936 at gmail.com>: > > > Hello, > > > > I just realized that 1^NA outputs 1 while 1.1^NA outputs NA in R v3.3.1and> > R v3.2.3. > > I tried other values such as 0^NA and 2^NA, and they all output NA. > > I don't understand this inconsistency here. Shouldn't 1^NA output NA as > > well? Why does R handle it differently? Or is this a bug in these > > particular versions of R? > > > > Thanks, > > Da > > > > [[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. > > > > [[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 guidehttp://www.R-project.org/posting-guide.html> and provide commented, minimal, self-contained, reproducible code.[[alternative HTML version deleted]]