Good question. It turns out that the manual page does not tell the whole story. Looking at the source code for hist.default, the function starts with the number of breaks suggested by nclass.Sturges(), but then this number (or any other number of breaks that you specify) is passed to pretty() along with the maximum and the minimum values of the data (ie range(data)) to create "pretty" break intervals. In your example, nclass.Sturges() always recommends 8 breaks, but the number of the breaks changes based on the minimum and maximum values. So the only way to get exactly the number of breaks you want is to specify the break intervals yourself.
David Carlson -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of philippe massicotte Sent: Wednesday, September 4, 2013 3:02 PM To: Rui Barradas Cc: r-help@R-project.org Subject: Re: [R] Histogram Thank you everyone. Try executing this: replicate(100, length(hist(rnorm(100), nclass = 10)$counts)) I'm still not sure why the number of bins (classes) is not consistent. Thank in advance. > Date: Wed, 4 Sep 2013 20:27:36 +0100 > From: ruipbarra...@sapo.pt > To: pmassico...@hotmail.com > CC: r-help@r-project.org > Subject: Re: [R] Histogram > > Hello, > > See the arguments 'right' and 'include.lowest' of ?hist. > To give what you want, try instead > > h1 <- hist(1:10, 10) # counts are 2, 1, 1, ... > h2 <- hist(1:10, breaks = 0:10) # all counts are 1 > > > and see the difference between h1 and h2, components 'breaks' and 'counts'. > > Hope this helps, > > Rui Barradas > > Em 04-09-2013 19:34, philippe massicotte escreveu: > > Hi everyone. > > I'm currently translating some Matlab code into R. However, I realized that the hsit function produce different results in both languages. > > in Matlab, hist(1:10, 10) will produce 10 bins with a count of 1 in each, but in R it will produce 9 classes with count of 2,1,1,1,1,1,1,1,1. > > I'm a bit embarrassed to ask such question, but why R is not producing 10 classes as requested? > > Thanks in advance,Phil > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@r-project.org mailing list > > 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 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 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.
