Stop matplotlib repeating labels in legend

Question

Here is a very simplified example:

xvalues = [2,3,4,6]

for x in xvalues:
    plt.axvline(x,color=\'b\',label=\'xvalues\')

plt.legend()

Th

Answer 1

These code snippets didn't work for me personally. I was plotting two different groups in two different colors. The legend would show two red markers and two blue markers, when I only wanted to see one per color. I'll paste a simplified version of what did work for me:

Import statements

import matplotlib.pyplot as plt

from matplotlib.legend_handler import HandlerLine2D

Plot data

points_grp, = plt.plot(x[grp_idx], y[grp_idx], color=c.c[1], marker=m, ms=4, lw=0, label=leglab[1])        
points_ctrl, = plt.plot(x[ctrl_idx], y[ctrl_idx], color=c.c[0], marker=m, ms=4, lw=0, label=leglab[0])

Add legend

points_dict = {points_grp: HandlerLine2D(numpoints=1),points_ctrl: HandlerLine2D(numpoints=1)}
leg = ax.legend(fontsize=12, loc='upper left', bbox_to_anchor=(1, 1.03),handler_map=points_dict)