matplotlib中的传奇

Question

我想知道如何执行以下操作： 我有一个DataFrame点和类。我想绘制所有点并为每个类使用一种颜色。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

让图例为每种颜色设置单独条目（因此它是target值）的最简单方法是为每个 target值创建单独的绘图对象

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()