[R] hist{graphics}

[Martin Maechler]

>>>>> Duncan Murdoch 
>>>>>     on Sat, 13 Jul 2019 05:29:18 -0400 writes:

    > On 12/07/2019 11:38 a.m., Steven wrote:
    >> Never mind. Thanks.
    >> 
    >> I found that adding parameter right=F to the call fixes it.

    > Drawing a histogram of discrete data often leads to bad results. 
    > Histograms are intended for continuous data, where no observations fall 
    > on bin boundaries.

    > You often get a more faithful representation of discrete data using 
    > something like

    >   plot(table(x))

    > Duncan Murdoch

yes!!
	including   plot(<factor>)  
 
[ if you really want, you can add something like   'lwd = 4' there ]

And relatedly, possibly more generally:

Many many people and hence useRs do
*NOT* distinguish between what R (and I think statistical graphics more
generally) calls  *histograms*  on one side vs
*bar plots* / *bar charts* / "spear charts"(?) etc on the other.

As Duncan said: Visually distinguishing quantities that are
inherently (mostly/almost) continuous ["mostly/..": think of quantum physics]
from those that are inherently "integer-like" or  categorical.

We (the R user community, notably the graphically oriented
subset) should really strive to keep these concepts and the
corresponding visualizations separate as well as possible
[and educate the consumers of our graphics if necessary ..]

Martin Maechler
ETH Zurich and R Core Team

    >> On 2019/7/12 下午 05:10, Steven wrote:
    >>> # Can someone help with this simple frequency histogram problem (n = 15)?
    >>> # I use four class limits: [90,95], [95,100], [100,105], [105,110].
    >>> # These coincide with the limits obtain by pretty {base}.
    >>> # Proper frequencies would be: (1,5,6,3).
    >>> # But hist{graphics} gives me a histogram showing frequencies (1,8,3,3),
    >>> # with or without argument break = ...
    >>> # Replicable codes below. Thanks.
    >>> 
    >>> set.seed(123)
    >>> x<-rnorm(15,mean=100,sd=5); x<-as.integer(x)
    >>> x<-sort(x)
    >>> x
    >>> breaks<-seq(90,110,by=5); breaks
    >>> pretty(x,n=5) # pretty {base}
    >>> x.cut<-cut(x,breaks,right=F) ; x.cut
    >>> freq<-table(x.cut); cbind(freq)
    >>> hist(x,breaks=breaks) # hist {graphics}
    >>> hist(x)
    >>> 
    >>> 
    >>> 
    >> 
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    >> 

    > ______________________________________________
    > R-help using 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.