Manually set color of points in legend

Question

I'm making a scatter plot which looks like this:

(MWE at bottom of question)

As can be seen in the image above the colors of the points in the legend are set to blue automatically by matplotlib. I need to set this points to some other color not present in the colormap (ie: black) so they won't generate confusion with the colors associated with said colormap.

I looked around but the matplotlib.legend module does not seem to accept a color keyword. Is there any way to do this?

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Here's the MWE:

import matplotlib.pyplot as plt import numpy as np  def rand_data():     return np.random.uniform(low=0., high=1., size=(100,))  # Generate data. x, y, x2, x3 = [rand_data() for i in range(4)] # This data defines the markes and labels used. x1 = np.random.random_integers(7, 9, size=(100,))  # Order all lists so smaller points are on top. order = np.argsort(-np.array(x2)) # Order x and y. x_o, y_o = np.take(x, order), np.take(y, order) # Order list related to markers and labels. z1 = np.take(x1, order) # Order list related to sizes. z2 = np.take(x2, order) # Order list related to colors. z3 = np.take(x3, order)  plt.figure() cm = plt.cm.get_cmap('RdYlBu')  # Scatter plot where each value in z1 has a different marker and label # assigned. mrk = {7: ('o', '7'), 8: ('s', '8'), 9: ('D', '9')} for key, value in mrk.items():      s1 = (z1 == key)     plt.scatter(x_o[s1], y_o[s1], marker=value[0], label=value[1],         s=z2[s1] * 100., c=z3[s1], cmap=cm, lw=0.2)  # Plot colorbar plt.colorbar()  # Plot legend. plt.legend(loc="lower left", markerscale=0.7, scatterpoints=1, fontsize=10)  plt.show() 

Answer 1

You can obtain the legend handles and change their colors individually:

ax = plt.gca() leg = ax.get_legend() leg.legendHandles[0].set_color('red') leg.legendHandles[1].set_color('yellow') 

Answer 2

You can retrieve the label of each legend handle with lh.get_label() if you want to map colors to specific labels.

For my purposes it worked best to create a dict from legendHandles and change the colors like so:

ax = plt.gca() leg = ax.get_legend() hl_dict = {handle.get_label(): handle for handle in leg.legendHandles} hl_dict['9'].set_color('red') hl_dict['8'].set_color('yellow')