Set number of bins for histogram directly in ggplot

Question

I'd like to feed geom_histogram the number of bins for my histogram instead of controlling bins through binwidth. The documentation says I can do this by setting the bins argument. But when I run

ggplot(data = iris, aes(x = Sepal.Length)) + stat_bin(bins = 5)

I get an output message with 30 bins, as if I didn't specify binwidth at all.

stat_bin: binwidth defaulted to range/30. Use 'binwidth = x' to adjust this.

I've tried feeding this argument to stat_bin and qplot with the same problem. Am I doing something wrong?

I'm using ggplot2 version 1.0.1.

@Heroka I've added version information to the question. I'm using version 1.0.1. Would R version info be useful too, in this case? — Empiromancer, Jan 13 '16 at 18:31
If you update to ggplot 2.0 the stat_bin(bins = x) command should work. — bouncyball, Jan 13 '16 at 18:31
works for me. consider updating ggplot and/or restarting your r session. — mtoto, Jan 13 '16 at 18:31
It works fine for me, but oddly: it always produces one more bin than I specify. An index-0 bug? (ggplot 2.0.0) — alistaire, Jan 13 '16 at 18:35
Oh interesting, @alistaire -- yes, same result illustrated below — arvi1000, Jan 13 '16 at 18:39
Opened [an issue report](https://github.com/hadley/ggplot2/issues/1487) on GitHub. — alistaire, Jan 13 '16 at 19:15

score 50 · Accepted Answer · answered Jan 13 '16 at 18:31

50

Just pass bins=x directly

library(ggplot2)
df <- data.frame(a = rnorm(10000))

ggplot(df, aes(x=a)) + geom_histogram()

Produces this (with warning "stat_bin() using bins = 30. Pick better value with binwidth."):

And this:

ggplot(df, aes(x=a)) + geom_histogram(bins=10)

Produces:

Using ggplot2 version 2.0.0

answered Jan 13 '16 at 18:31

arvi1000

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Hat tip to @bouncyball, apparently you commented to the same effect while I was writing this – arvi1000 Jan 13 '16 at 18:37

Set number of bins for histogram directly in ggplot

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