R help - Jan 2013 - Wrong bin count number with hist() ?

Hi there,

# Consider the following example:

A = 19
B = 20
A< B
A==B
hist(c(1:15,B,50),breaks=c(0,15,A,50),plot=F)$count
hist(c(1:15,A,50),breaks=c(0,15,B,50),plot=F)$count

# I was expecting the same results with the following values of A and B:

A = 19.6019203953960
B = 19.6019204365543
A< B
A==B
hist(c(1:15,B,50),breaks=c(0,15,A,50),plot=F)$count# wrong
hist(c(1:15,A,50),breaks=c(0,15,B,50),plot=F)$count# correct

# Note that truehist() of MASS define the bin count number "correctly"
require(MASS)
par(mfrow=c(1,2))
? ? ?hist(c(1:15,B,50),breaks=c(0,15,A,50),col="light
gray",main="wrong - hist()")
truehist(c(1:15,B,50),breaks=c(0,15,A,50),main="correct - truehist()")

# I was not able to find?an explanation?online or in the R documentation.?
# The option "include.lowest" doesn't help in such cases.
# Any clue to get the correct count number per bin ?

Regards,
Ken

Ken Mailinglist? Sounds like a modern version of the Abbott and Costello
"Who's On First" routine.

Anyway, this seems like an excellent opportunity to point out that you can get
help on any base or loaded package function using the ? symbol. E.g.

?hist

If you feel the help file is insufficient, please pass along any constructive
criticism (or patches to improve it) AFTER you read it carefully. You might also
find reading the code informative in some cases... just type the full name of
the function at the R command line prompt:

hist.default

Figuring out that you have to add "default" to the name isn't so
obvious at first, I must admit, but it is one price we pay in R for being able
to do similarly named actions on different kinds of objects.
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Sent from my phone. Please excuse my brevity.

ken.mailinglist at me.com wrote:
>Hi there,
>
># Consider the following example:
>
>A = 19
>B = 20
>A< B
>A==B
>hist(c(1:15,B,50),breaks=c(0,15,A,50),plot=F)$count
>hist(c(1:15,A,50),breaks=c(0,15,B,50),plot=F)$count
>
># I was expecting the same results with the following values of A and
>B:
>
>A = 19.6019203953960
>B = 19.6019204365543
>A< B
>A==B
>hist(c(1:15,B,50),breaks=c(0,15,A,50),plot=F)$count# wrong
>hist(c(1:15,A,50),breaks=c(0,15,B,50),plot=F)$count# correct
>
># Note that truehist() of MASS define the bin count number
"correctly"
>require(MASS)
>par(mfrow=c(1,2))
>? ? ?hist(c(1:15,B,50),breaks=c(0,15,A,50),col="light
gray",main="wrong
>- hist()")
>truehist(c(1:15,B,50),breaks=c(0,15,A,50),main="correct -
truehist()")
>
># I was not able to find?an explanation?online or in the R
>documentation.?
># The option "include.lowest" doesn't help in such cases.
># Any clue to get the correct count number per bin ?
>
>Regards,
>Ken
>
>
>______________________________________________
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