[R] hist function to give each cell equal area

[Dan Bolser]

On Fri, 7 Jan 2005, BXC (Bendix Carstensen) wrote:

>how about:
>
>x <- rnorm(400)
>nbin<-7
>hist(x,breaks=quantile(x,prob=seq(0,1,length=nbin+1)))

Thanks for the replies! Quantiles are my new friend. Its true the example
I gave was a bit tricky, I just wanted to get the idea over.

One thing that is slightly confusing (probably a slight syntax thing),
combining the above with the reply from Peter Dalgaard...

nbin<-10
x <- rnorm(400)
hist(x,breaks=quantile(x,prob=seq(0,1,length=nbin+1)))

y <- table(cut(x,breaks=quantile(x,seq(0,1,length=nbin+1))))

> y
[1] 399

I only get 399 counts out, and I put 400 counts in?

Cheers,
Dan.

>
>Bendix Carstensen
>----------------------
>Bendix Carstensen
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>
>> -----Original Message-----
>> From: r-help-bounces at stat.math.ethz.ch 
>> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Dan Bolser
>> Sent: Friday, January 07, 2005 11:21 AM
>> To: R mailing list
>> Subject: [R] hist function to give each cell equal area
>> 
>> 
>> 
>> Hi,
>> 
>> I want to use hist with non-equi-spaced breaks, picked such 
>> that the fraction of the data points falling in the cells 
>> (defined by 'breaks') is 
>> roughly equal accross all cells.
>> 
>> Is there such a function that will automatically try to 
>> determine the breaks to fullfill this requirement?
>> 
>> Something like..
>> 
>> hist( x, br = magic_function_to_pick_breaks())
>> 
>> 
>> For example, if x looked like this...
>> 
>> x <- c( 1:5, 10+1:5, 100+1:5 )
>> 
>> the breaks would define cells like this 
>> 
>> hist(x,breaks=c(0,5,15,105))
>> 
>> Is there such a function?
>> 
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>