How do you make an errorbar plot in matplotlib using linestyle=None in rcParams?

Question

When plotting errorbar plots, matplotlib is not following the rcParams of no linestyle. Instead, it's plotting all of the points connected with a line. Here's a minimum working example:

import matplotlib.pyplot as plt  lines = {'linestyle': 'None'} plt.rc('lines', **lines)  plt.errorbar((0, 1), (1, 0), yerr=(0.1, 0.1), marker='o')  plt.savefig('test.pdf') plt.delaxes() 

Is the only solution to explicitly set linestyle='None' when calling pyplot.errorbar()?

Answer 1

This is a "bug" in older versions of matplotlib (and has been fixed for the 1.4 series). The issue is that in Axes.errorbar there is a default value of '-' for fmt, which is then passed to the call to plot which is used to draw the markers and line. Because a format string is passed into plot in never looks at the default value in rcparams.

You can also pass in fmt = ''

eb = plt.errorbar(x, y, yerr=.1, fmt='', color='b') 

which will cause the rcParam['lines.linestlye'] value to be respected. I have submitted a PRto implement this.

Another work around for this is to make the errorbar in two steps:

l0, = plt.plot(x,y, marker='o', color='b') eb = plt.errorbar(x, y, yerr=.1, fmt=None, color='b') 

This is an annoying design decision, but changing it would be a major api break. Please open an issue on github about this.

errorbar doc.

As a side note, it looks like the call signature was last changed in 2007, and that was to make errorbars not default to blue.

Answer 2

Using: fmt='' indeed doesn't work. One needs to put something that is not an empty string. As mentioned by @strpeter, a dot or any other marker would work. Examples: fmt='.' fmt=' ' fmt='o'