How can I set the dash length in pyplot.hist?

Question

I know the dashes length and gap size can be set in plt.plot but is there a way to do so in plt.hist? This is what my command looks like: plt.hist(x, bins=5, range=(7.,11.), facecolor='None', linestyle='dashed', linewidth=2, normed=1)

Setting of line styles has been unified on master. – tacaswell Jul 02 '15 at 19:06 — tacaswell, Jul 02 '15 at 19:06

score 1 · Answer 1 · edited Mar 07 '16 at 11:27

1

Simply read up on the official documentation:

set_dashes is a function that takes a sequence of on and off lengths in points.

So set_dashes((3,3)) should produce something different then set_dashes((15,15)).

Now, for hist that won't really work, since setting the line properties, at best, will change the appearance of the outline.

What you can do instead is

use numpy's histogram function; it's used by pyplot's hist, anyway, and then
plot the results using stem.

edited Mar 07 '16 at 11:27

Will Vousden

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answered Jul 02 '15 at 12:29

Marcus Müller

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`set_dashes()` works with something like `lines, = plt.plot(x)` and then `lines.set_dashes(...)`. But the `hist` function does not allow to store the plot into a variable. Or does it? – amid Jul 02 '15 at 13:09
@tcaswell: um, no. actually, using stem would give you the ability to plot lines instead of rectangles. – Marcus Müller Jul 03 '15 at 14:28
@MarcusMüllerꕺꕺ: not sure how to get `stem` to plot a histogram. Is that possible? I checked the documentation but got nothing. – amid Jul 03 '15 at 15:23
a histogram is just a set of heights, right? so nothing a stem plot can't visualize. – Marcus Müller Jul 03 '15 at 17:05

score 1 · Answer 2 · edited Sep 18 '20 at 05:08

As another answer pointed out the set_dashes method does not work for histograms. However, you can achieve fine control over the linestyle by passing a dash tuple directly to "linestyle" (see the documentation here https://matplotlib.org/3.1.0/gallery/lines_bars_and_markers/linestyles.html)

In your example, you could achieve the "loosely dashed" style in the link as follows

x=[7]*10
plt.hist(x, bins=5, range=(7.,11.), ec='k', facecolor='None', 
         linewidth=2, normed=1, linestyle=(0,(5,10)))

This works for me with matplotlib 3.0.3. Note I also, had to add ec='k' to get the outline of the histogram to appear at all...

How can I set the dash length in pyplot.hist?

2 Answers2