hist() and bar spacing

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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,

Am?lie Lescro?l

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...
I obtain this kind of histogram (what I actually want), i.e. large bars with
no space between them

 ...
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.

... 

I suspect that it?s causing me some troubles to fit my data to a probability
density function. Using:

Hi Amelie,

Them's the breaks. Try this:

hist(test,breaks=-1:7)

and you should get what you want.

Jim