熊猫图：使用数据框列作为两级 x 轴次要和主要刻度标签

Question

这是我用来生成下面条形图的数据和代码：

import pandas as pd
import matplotlib.pyplot as plt

data = [["2019","Jan.", 2000,2200,-200],
        ["2019","Feb.", 1500,1400,100],
        ["2019","Dec.", 1200,1100,100],
        ["2020","Jan.", 1400,1300,100],
        ["2020","Dec.", 1300,1200,100]]

df = pd.DataFrame(data, columns=["Year", "Month", "incomes", "expenses", "Balance"])
df.plot.bar()
plt.show()

不过，我想使用 df["Year"] 作为主要刻度标签，使用 df["Month"] 作为次要标签，而不是序号。

这是怎么做到的？

Answer 1

您可以通过遍历数据框来创建标签，通过连接年份和月份来创建字符串。

import pandas as pd
import matplotlib.pyplot as plt

data = [["2019", "Jan.", 2000, 2200, -200],
        ["2019", "Feb.", 1500, 1400, 100],
        ["2019", "Dec.", 1200, 1100, 100],
        ["2020", "Jan.", 1400, 1300, 100],
        ["2020", "Dec.", 1300, 1200, 100]]
df = pd.DataFrame(data, columns=["Year", "Month", "incomes", "expenses", "Balance"])
ax = df.plot.bar()
ax.set_xticks(range(len(df)))
ax.set_xticklabels([f"{month}\n{year}" for year, month in zip(df["Year"], df["Month"])], rotation=0)
plt.show()