[R] hist() and bar spacing

[Uwe Ligges]

Amelie LESCROEL wrote:
> Hello,
> 
>  
> 
> Could someone explain to me why I get so different histograms, in terms of
> bar spacing, depending on the number of counts entered ? (see example below)
> 
>  
> 
>> test <- c(0,1,1,1,1,0,0,0,0,0,2,3,2,2,2,3,3,4,5,6,7,5,4,3,4,2,2)
> 
>> hist(test)
> 
>  
> 
> I obtain this kind of histogram (what I actually want), i.e. large bars with
> no space between them
> 
>  
> 
> x
> 
> xx
> 
> xxx
> 
> xxxx
> 
> xxxxx
> 
> xxxxxx
> 
> xxxxxxx
> 
> xxxxxxxxx
> 
> xxxxxxxxxx
> 
>  
> 
> Entering:
> 
>> test <-
> c(3,1,2,1,1,1,2,1,1,2,2,2,0,1,1,1,3,0,0,2,5,2,0,0,1,6,0,1,1,4,0,0,2,1,0,1,3,
> 0,0,0,3,2,1,3,6,3,1,0,1,0,1,0,1,0,0,4,1,3,2,7,5,1,0,0,1,2,0,2,0,2,0,2,1,1,3,
> 1,3,0,2,1,3,1,1,0,1,7,2,1,2,2,2,1,2,5,1,2,2,2,1,1,4,2,0,4,1,1,1,5,1,0,2,5,2,
> 1,1,1,1,2,1,1,1,1,4,2,1,3,1,1,2,4,2,1,1,1,1,1,1,1,1,1,4,1,0,2,2,5,1,4,0,1,2,
> 2,2,2,1,2,1,3,5,2,0,0,2,0,0,0,0,1,1,2,2,1,1,2,1,0,1,0,2,1,3,0,0,0,1,3,1,3,1,
> 0,3,1,2,0,1,1,1,3,4,4,2,1,1,1,2,1,2,2,5,1,1,1,1,1,2,0,1,3,1,1,2,3,1,1,2,0,0,
> 2,0,1,1,1,1,1,1,1,1,1,1,5,3,1,1,1,0,0,1,0,1,1,0,0,1,2,0,0,0,2,3,1,1,1,2,0,0,
> 0,0,0,0,0,0,0,0,0,0,0,0,1,1,2,0,1,0,0,0,1,3,0,1,3,1,2,1,1,2,1,1,3,1,1,1,0,0,
> 1,1,1,1,1,1,1,1,4,1,3,3,1,2,1,2,3,4,1,0,2,2,1,2,1,2,3,0,0,2,3,2,4,1,0,1,1,0,
> 1,3,2,3,3,1,3,1,0,2,1,1,1,1,1,1,3,0,0,1,1,1,1,1,1,3,1,3,3,0,1,2,1,2,3,1,2,1,
> 2,2,2,1,1,1,1,0,2,2,1,2,2,2,1,1,2,2,1,1,1,2,2,1,1,1)

You data follows a *discrete* distribution, hence a barplot seems to be 
more appropriate here:

barplot(table(testtest))

Uwe Ligges




>> hist(test)
> 
>  
> 
> I obtain a strange histogram with the first 2 bars grouped together and then
> thin bars (not occupying the entire bin width) separated by spaces.
> 
>  
> 
>   x
> 
>   x   x
> 
> xx   x
> 
> xx   x   x
> 
> xx   x   x   x
> 
> xx   x   x   x   x
> 
> xx   x   x   x   x
> 
> xx   x   x   x   x   x
> 
> xx   x   x   x   x   x   x
> 
> xx   x   x   x   x   x   x   x   x 
> 
>  
> 
> I suspect that it’s causing me some troubles to fit my data to a probability
> density function. Using:
> 
>  
> 
>> plot(density(test))
> 
>  
> 
> I got a “wave-shaped” density line, with the line going down to zero between
> each bar. And I wouldn’t expect the density line to go down between each
> integer… or surely there is something that I don’t understand!
> 
>  
> 
> Thanks for your help,
> 
>  
> 
> Amélie Lescroël
> 
>  
> 
>  
> 
>  
> 
> 
> 	[[alternative HTML version deleted]]
> 
> 
> 
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