当小时和分钟在不同的pandas列中时，我如何绘制它们？

pip install pandas
pip install matplotlib

import pandas as pd
import matplotlib.pyplot as plt

data = {'hour': [1, 2, 3, 4, 5],
        'minute': [30, 45, 15, 10, 20]}
df = pd.DataFrame(data)

df['time'] = pd.to_datetime(df['hour'].astype(str) + ':' + df['minute'].astype(str), format='%H:%M')

df.set_index('time', inplace=True)

df.plot()
plt.show()