如何在特定日期范围内对pandas列DataFrame中的特定值求和

import pandas as pd

# 创建一个示例DataFrame对象
data = {'日期': ['2022-01-01', '2022-01-02', '2022-01-03', '2022-01-04'],
        '数值': [10, 20, 30, 40]}
df = pd.DataFrame(data)

# 将日期列转换为日期时间类型
df['日期'] = pd.to_datetime(df['日期'])

# 筛选特定日期范围内的行
start_date = '2022-01-02'
end_date = '2022-01-04'
mask = (df['日期'] >= start_date) & (df['日期'] <= end_date)
filtered_df = df.loc[mask]

# 对筛选后的数值列求和
sum_value = filtered_df['数值'].sum()

print("特定日期范围内的数值求和结果为:", sum_value)