[R] Histograms per coding variable

[Ben Bolker]

 Something like

tapply(fr.wt,site,hist,nclass=20)

e.g.:

a <- runif(100)
f <- factor(rep(1:10,rep(10,10)))
par(mfrow=c(3,4))
tapply(a,f,hist)

On Wed, 5 Dec 2001, Smit, A, Albertus, Dr wrote:

> Dear all
>
> I have a dataset that looks like:
>
> 	fr.wt		site
> 1	4400		glen
> 2	235		glen
> 3	225		glen
> '	'		'
> '	'		'
> '	'		'
> 82	550		glen
> 83	550		kom
> 84	550		kom
> '	'		'
> '	'		'
> '	'		'
> 191	820		kom
> 192	2000		soet
> '	'		'
> '	'		'
>
> I need to do a series of histograms for each of the codes, levels or
> factors in 'site'.  For the first one, 'glen', I would do:
>
> >hist(fr.wt[1:82], nclass = 20)
>
> for the second, 'kom':
>
> >hist(fr.wt[83:191], nclass = 20)
>
> and so on.
>
> Is there are more elegant way to do this without having to use the
> fr.wt[1:82] bit?  I.e., how else can one extract the fr.wt data
> relevant to each code in the 'site' column?  If there is, say, 20
> codes in the 'site' column, how can one produce a histogram for each
> without having the retype the hist() bit for each code individually?
>
> I am sure there is an easy solution which I am overlooking.
>
> Thanks for the help,
> Albertus
>
>
> Dr Albertus J. Smit
> Department of Botany
> University of Cape Town
> PO Box Rondebosch
> 7700
> SOUTH AFRICA
> Tel. 689 3032
> Fax. 650 4041
>
> -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
> r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
> Send "info", "help", or "[un]subscribe"
> (in the "body", not the subject !)  To: r-help-request at stat.math.ethz.ch
> _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
>

-- 
318 Carr Hall                                bolker at zoo.ufl.edu
Zoology Department, University of Florida    http://www.zoo.ufl.edu/bolker
Box 118525                                   (ph)  352-392-5697
Gainesville, FL 32611-8525                   (fax) 352-392-3704

-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._