pandas 在 DataFrame 聚合后绘制特定列
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Plot specific column after DataFrame aggregation
提问by Michal
I would like to plot a bar and line graph of specific columns.
我想绘制特定列的条形图和折线图。
Using aggfunction I got as many new columns as there are functions.
What can I do if I want to plot only column sum of Aand mean of Bcolumn ?
使用agg函数，我得到了与函数一样多的新列。如果我只想绘制列的总和A和列的均值，我该怎么办B？
Below you can find my code, where all columns are plotted.
您可以在下面找到我的代码，其中绘制了所有列。
index=pd.date_range('2013-1-1 00:00', '2013-12-31 23:00', freq='1h')
df=pd.DataFrame(np.random.rand(len(index),2),index=index, columns=['A','B'])
df2=df.groupby(lambda x: x.month).agg({'A' : [np.mean, np.sum], 'B': np.mean})
fig = plt.figure()
ax = df2['A'].plot(kind="bar");plt.xticks(rotation=0)
ax2 = ax.twinx()
ax2.plot(ax.get_xticks(),df2['B'],marker='o')
Could you be able to give me some hints how to solve this ? Thank you in advance!
你能给我一些如何解决这个问题的提示吗？先感谢您！
回答by 8one6
You have a hierarchical index. So you just need to select the right columns using the tuplesyntax.
您有一个分层索引。所以你只需要使用tuple语法选择正确的列。
So instead of:
所以而不是：
ax = df2['A'].plot(kind="bar")
use:
用：
ax = df2[('A', 'sum')].plot(kind="bar")
and instead of:
而不是：
ax2.plot(ax.get_xticks(),df2['B'],marker='o')
use:
用：
ax2.plot(ax.get_xticks(),df2[('B', 'mean')],marker='o')
Putting it all together:
把它们放在一起：
import numpy as np
import pandas as pd
import seaborn as sbn
import matplotlib.pyplot as plt
np.random.seed(0)
index = pd.date_range('2013-1-1 00:00', '2013-12-31 23:00', freq='1h')
df = pd.DataFrame(np.random.rand(len(index),2),index=index, columns=['A','B'])
df2 = df.groupby(lambda x: x.month).agg({'A' : [np.mean, np.sum], 'B': np.mean})
fig = plt.figure()
ax = df2[('A', 'sum')].plot(kind="bar", alpha=0.7)
plt.xticks(rotation=0)
ax2 = ax.twinx()
ax2.plot(ax.get_xticks(),df2[('B', 'mean')],marker='o', c='navy', linewidth=4)
gives you a nice graph:
给你一个漂亮的图表：
