在 matplotlib 中自定义图例 [英] Customizing legend in matplotlib

问题描述

我正在 matplotlib 中绘制具有不同颜色的矩形.我希望每种类型的矩形都有一个在图例中出现一次的标签.我的代码是:

import matplotlib.patches 作为补丁fig1 = plt.figure()ax = plt.subplot(1,1,1)次数 = [0, 1, 2, 3, 4]对于 t 次:如果 % 2 == 0:颜色=蓝色"别的:颜色=绿色"ax.add_patch(patches.Rectangle((t, 0.5), 0.1, 0.1,脸色=颜色，标签=颜色))plt.xlim(times[0],times[-1] + 0.1)plt.legend()plt.show()

问题是每个矩形在图例中出现多个.我只想在图例中有两个条目:一个标记为蓝色"的蓝色矩形和一个标记为绿色"的绿色矩形.如何实现?

解决方案

如文档所述

i'm plotting rectangles that have different colors in matplotlib. i would like each type of rectangle to have a single label that appears once in the legend. my code is:

import matplotlib.patches as patches
fig1 = plt.figure()
ax = plt.subplot(1,1,1)
times = [0, 1, 2, 3, 4]
for t in times:
    if t % 2 == 0:
        color="blue"
    else:
        color="green"
    ax.add_patch(patches.Rectangle((t, 0.5), 0.1, 0.1,
                                   facecolor=color,
                                   label=color))
plt.xlim(times[0], times[-1] + 0.1)
plt.legend()
plt.show()

the problem is that each rectangle appears multiple in the legend. i would like to only have two entries in the legend: a blue rectangle labeled "blue", and a green rectangle labeled "green". how can this be achieved?

解决方案

As documented here, you can control the legend by specifying the handles to the graphical objects for which you want the legends. In this case, two out of the five objects are needed, so you can store them in a dictionary

import matplotlib.pyplot as plt
import matplotlib.patches as patches
fig1 = plt.figure()
ax = plt.subplot(1,1,1)
times = [0, 1, 2, 3, 4]
handle = {}
for t in times:
    if t % 2 == 0:
        color="blue"
    else:
        color="green"
    handle[color] = ax.add_patch(patches.Rectangle((t, 0.5), 0.1, 0.1,
                                   facecolor=color,
                                   label=color))
plt.xlim(times[0], times[-1] + 0.1)
print handle
plt.legend([handle['blue'],handle['green']],['MyBlue','MyGreen'])
plt.show()

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