如何在dataframe中更改不同的值

import pandas as pd

df = pd.DataFrame({'A': [1, 2, 3, 4, 5],
                   'B': [6, 7, 8, 9, 10],
                   'C': [11, 12, 13, 14, 15]})

# 将列A中大于3的值更改为100
df.loc[df['A'] > 3, 'A'] = 100

# 将列B中等于7的值更改为200
df.loc[df['B'] == 7, 'B'] = 200

# 将列C中小于等于13的值更改为300
df.loc[df['C'] <= 13, 'C'] = 300

print(df)