[R] Histogram of multiple series on one histogram

[Depire Alexandre]

Hello,
I have three sample, for example
	a<-c(10,20,10,20,30)
	b<-c(10,20,20,30,30)
	c<-c(20,20,10)

I would like to have only one histogram with these series,
I try the following code:
	hist(a)
	hist(b,add=TRUE,col="red")
	hist(c,add=TRUE,col="green")
but it's not that I want 

I would like an histogram with, from left to right, count of "10" for "a", 
count of "10" for "b", count of "10" for "c", count of "20" for "a", count of 
"20" for "b", ... not overlapped

Thanks


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Alexandre DEPIRE
INRETS / GARIG
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