How to remove gaps between bars in Matplotlib bar chart

Question

I'm making a bar chart in Matplotlib with a call like this:

xs.bar(bar_lefts, bar_heights, facecolor='black', edgecolor='black') 

I get a barchart that looks like this:

What I'd like is one with no white gap between consecutive bars, e.g. more like this:

Is there a way to achieve this in Matplotlib using the bar() function?

Answer 1

Add width=1.0 as a keyword argument to bar(). E.g.

xs.bar(bar_lefts, bar_heights, width=1.0, facecolor='black', edgecolor='black').

This will fill the bars gaps vertically.

Answer 2

It has been 8 years since this question was asked, and the matplotlib API now has built-in ways to produce filled, gapless bars: pyplot.step() and pyplot.stairs() with the argument fill=True.

See the docs for a fuller comparison, but the primary difference is that step() defines the step positions with N x and N y values just like plot() would, while stairs() defines the step positions with N heights and N+1 edges, like what hist() returns. It is a subtle difference, and I think both tools can create the same outputs.