[R] histogram first bar wrong position

[itpro]

Hi, everyone.


I stumbled upon weird histogram behaviour.

Consider this "dice emulator":
Step 1: Generate uniform random array x of size N.
Step 2: Multiply each item by six and round to next bigger integer to get numbers 1 to 6.
Step 3: Plot histogram.

> x<-runif(N)
> y<-ceiling(x*6)
> hist(y,freq=TRUE, col='orange')


Now what I get with N=100000

> x<-runif(100000)
> y<-ceiling(x*6)
> hist(y,freq=TRUE, col='green')

At first glance looks OK.

Now try N=100

> x<-runif(100)
> y<-ceiling(x*6)
> hist(y,freq=TRUE, col='red')

Now first bar is not where it should be.
Hmm. Look again to 100000 histogram... First bar is not where I want it, it's only less striking due to narrow bars.

So, first bar is always in wrong position. How do I fix it to make perfectly spaced bars?





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