使用Matplotlib以图例样式绘制离散色条

Question

有时，我想绘制pcolormesh样式的离散值。

例如，为了表示在100×100的形状的2-d阵列含有INT 0〜7

data = np.random.randint(8, size=(100,100)) 
cmap = plt.cm.get_cmap('PiYG', 8) 
plt.pcolormesh(data,cmap = cmap,alpha = 0.75) 
plt.colorbar() 

该图示出了这样的：

如何生成颜色条在传奇风格。换句话说，每个颜色框对应于其值（例如粉红颜色框 - > 0）

一个例证这里（不适合本示例）：

Answer 1

也许最简单的方法是创建修补实例的相应数量：

import matplotlib.patches as mpatches 
import matplotlib.pyplot as plt 
import numpy as np 

data = np.random.randint(8, size=(100,100)) 
cmap = plt.cm.get_cmap('PiYG', 8) 
plt.pcolormesh(data,cmap = cmap,alpha = 0.75) 
# Set borders in the interval [0, 1] 
bound = np.linspace(0, 1, 9) 
# Preparing borders for the legend 
bound_prep = np.round(bound * 7, 2) 
# Creating 8 Patch instances 
plt.legend([mpatches.Patch(color=cmap(b)) for b in bound[:-1]], 
      ['{} - {}'.format(bound_prep[i], bound_prep[i+1] - 0.01) for i in range(8)])