[R] Histogram

[Duncan Murdoch]

On 13-09-04 4:44 PM, David Carlson wrote:> Good question. It turns out 
that the manual page does not tell
 > the whole story.

Do you really think the manual page would be improved if it went into as 
much detail as you give below?  It does say clearly that breaks is a 
"suggestion only".  I don't think it would be clearer if it explained 
exactly how the suggestion is used. It would just be more complicated, 
and less likely to be read.

Duncan Murdoch


  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-bounces at r-project.org
 > [mailto:r-help-bounces at r-project.org] On Behalf Of philippe
 > massicotte
 > Sent: Wednesday, September 4, 2013 3:02 PM
 > To: Rui Barradas
 > Cc: r-help at 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: ruipbarradas at sapo.pt
 >> To: pmassicotte at hotmail.com
 >> CC: r-help at 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 at 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 at 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 at 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.
 >