How to set the line width of error bar caps, in matplotlib?

Question

How can the line width of the error bar caps in Matplotlib be changed?

I tried the following code:

(_, caplines, _) = matplotlib.pyplot.errorbar(
            


        

Answer 1

This is based on @joaquin's answer, but a little more concise (if you just want plain error caps with no special styling):

distance = [1,3,7,9]
energy = [10,20,30,40]
sigma = [1,3,2,5]

plt.errorbar(distance, 
    energy, 
    sigma, 
    capsize=5, 
    elinewidth=2,
    markeredgewidth=2)

Answer 2

EOL, you were very close..,

distance = [1,3,7,9]
energy = [10,20,30,40]
sigma = [1,3,2,5]

(_, caps, _) = plt.errorbar(distance, energy, sigma, capsize=20, elinewidth=3)

for cap in caps:
    cap.set_color('red')
    cap.set_markeredgewidth(10)

plt.show

set_markeredgewidth sets the width of the cap lines.

Matplotlib objects have so many attributes that often it is difficult to remember the right ones for a given object. IPython is a very useful tool for introspecting matplotlib. I used it to analyze the properties of the 2Dlines correponding to the error cap lines and I found that and other marker properties.

Cheers