Python Matplotlib-使用for循环打印分组值

我试图使用for循环绘制一个按列值分组的图，而不知道该列中唯一值的数量

您可以看到下面的示例代码（没有for循环）和所需的输出

我希望每个绘图都有不同的颜色和标记（如下所示）

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代码如下：

import pandas as pd
from numpy import random

df = pd.DataFrame(data = random.randn(5,4), index = ['A','B','C','D','E'],
columns = ['W','X','Y','Z'])

df['W'] = ['10/01/2018 12:00:00','10/03/2018 13:00:00',
           '10/03/2018 12:30:00','10/04/2018 12:05:00',
           '10/08/2018 12:00:15']

df['W']=pd.to_datetime(df['W'])

df['Entity'] = ['C201','C201','C201','C202','C202']

print(df.head()) 

fig, ax = plt.subplots()
df[df['Entity']=="C201"].plot(x="W",y="Y",label='C201',ax=ax,marker='x')
df[df['Entity']=="C202"].plot(x="W",y="Y",label='C202',ax=ax, marker='o')

这是输出：

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您可以首先找到

df['Entity']

的唯一值，然后循环遍历它们。要为每个实体自动生成新标记，您可以定义一些标记的顺序（比如下面的答案中的5个），这些标记将通过

marker=next（marker）

重复

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完成最小答案

import itertools
import pandas as pd
from numpy import random
import matplotlib.pyplot as plt

marker = itertools.cycle(('+', 'o', '*', '^', 's')) 
df = pd.DataFrame(data = random.randn(5,4), index = ['A','B','C','D','E'],
columns = ['W','X','Y','Z'])

df['W'] = ['10/01/2018 12:00:00','10/03/2018 13:00:00',
           '10/03/2018 12:30:00','10/04/2018 12:05:00',
           '10/08/2018 12:00:15']

df['W']=pd.to_datetime(df['W'])

df['Entity'] = ['C201','C201','C201','C202','C202']

fig, ax = plt.subplots()

for idy in np.unique(df['Entity'].values):
    df[df['Entity']==idy].plot(x="W",y="Y", label=idy, ax=ax, marker=next(marker))

plt.legend()
plt.show()