matplotlib中的图例

Question

我想知道如何执行以下操作： 我有一个带点和类的DataFrame。我想绘制所有点，并为每个班级使用一种颜色。我如何指定类如何引用图例中的颜色？

fig = plt.figure(figsize=(18,10), dpi=1600) 
df = pd.DataFrame(dict(points1 = data_plot[:,0], points2 = data_plot[:,1], \ 
      target = target[0:2000])) 
colors = {1: 'green', 2:'red', 3:'blue', 4:'yellow', 5:'orange', 6:'pink', \        
       7:'brown', 8:'black', 9:'white'} 
fig, ax = plt.subplots() 
ax.scatter(df['points1'], df['points2'], c = df['target'].apply(lambda x: colors[x])) 

Answer 1

，最简单的办法让你的传奇有单独的条目为每种颜色（因此它的target值）创建一个单独的情节对象每个target值。

import matplotlib.pyplot as plt 
import pandas as pd 
import numpy as np 

x = np.random.rand(100) 
y = np.random.rand(100) 
target = np.random.randint(1,9, size=100) 

df = pd.DataFrame(dict(points1=x, points2=y, target=target)) 
colors = {1: 'green', 2:'red', 3:'blue', 4:'yellow', 5:'orange', 6:'pink', \ 
       7:'brown', 8:'black', 9:'white'} 
fig, ax = plt.subplots() 

for k,v in colors.items(): 
    series = df[df['target'] == k] 
    scat = ax.scatter(series['points1'], series['points2'], c=v, label=k) 

plt.legend()