熊猫条形图总是会创建一个空的子图

Question

我想在一个图中绘制两个条形图，但我总是失败。

以下是我的代码：

def plot_data_group2(factor,xlabel): #xlabel: 这里是为了x轴坐标设置的
    survived_count=survived_passenger.groupby([factor])['PassengerId'].count()    
    fig_1 = plt.figure() #指定figure的宽和高，单位为英寸
    fig_1=plt.subplot(121)
    survived_count.plot(kind='bar')
    fig_1.set_title('Survived rate group by ' + factor)
    fig_1.set_xlabel(factor)
    fig_1.set_ylabel("count of the survived")
    plt.xticks(rotation=0) #旋转x轴的标签至水平（默认是和x轴垂直的）    
    fig_2=plt.subplot(122)
    survived_count_group = titanic_data.groupby([factor, 'Survived'])['PassengerId'].count().unstack()
    survived_rate = survived_count_group.apply(lambda x: (x / x.sum() * 100),axis=1)
    survived_rate.plot(kind='bar')
    fig_2.set_title('Survived rate group by ' + factor)
    fig_2.set_xlabel(factor)
    fig_2.set_ylabel("ration of " + factor + " in the survived")
    plt.xticks(rotation=0)    
    #plt.show()
plot_data_group2('Age_group',['under 18','young','not old','old'])

输出如下：

Answer 1

将survived_rate.plot(kind='bar')更改为survived_rate.plot(kind='bar', ax=fig_2)。

Answer 2

我不确切地知道为什么pandas DataFrame.plot与使用pyplot.plot绘制数据完全相同。

但是，您可以使用关键字参数将轴显式传递给DataFrame.plot。看看这个例子是否有意义。

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

# random test data
x = np.linspace(0, 1, 20)
y = x ** 2
# data in a pandas frame with 2 columns
df = pd.DataFrame([x, y]).T

fig, ax = plt.subplots(1, 2) # (n rows, n cols)
df.plot(0, 1, ax=ax[0])
df.plot(0, 1, ax=ax[1])
plt.show()