Python 手动设置图例中点的颜色
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Manually set color of points in legend
提问by Gabriel
I'm making a scatter plot which looks like this:
我正在制作一个散点图，如下所示：
(MWE at bottom of question)
（问题底部的 MWE）
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.
如上图所示，图例中点的颜色由 自动设置为蓝色matplotlib。我需要将此点设置为颜色图中不存在的其他颜色（即：黑色），这样它们就不会与与所述颜色图关联的颜色产生混淆。
I looked around but the matplotlib.legendmodule does not seem to accept a colorkeyword. Is there any way to do this?
我环顾四周，但matplotlib.legend模块似乎不接受color关键字。有没有办法做到这一点？
Here's the MWE:
这是 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()
采纳答案by Saullo G. P. Castro
You can obtain the legend handles and change their colors doing:
您可以通过以下方式获取图例句柄并更改其颜色：
ax = plt.gca()
leg = ax.get_legend()
leg.legendHandles[0].set_color('red')
leg.legendHandles[1].set_color('yellow')
回答by apteryx
You can retrieve the label of each legend handle with lh.get_label()if you want to map colors to specific labels.
lh.get_label()如果要将颜色映射到特定标签，可以使用 检索每个图例句柄的标签。
For my purposes it worked best to create a dict from legendHandles and change the colors like so:
出于我的目的，最好从 legendHandles 创建一个 dict 并像这样更改颜色：
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')
