python - Pandas:等效于 Excel sumifs

Question

对于下表，我如何实现与以下 SUMIFS 语句等效的 Python？

SUMIFS(A3:A7,B3:B7,"<="&C1,C3:C7,">0")

DataFrame 代码:

dfp = pd.DataFrame({'Value': [1223, 34, 34, 345],
                    'Date': ['04/03/2020', '06/04/2020','08/06/2020','12/12/2020'],
                    'Tval' : [0.01,0.015,-0.023,-0.0005]})

预期输出为 1257。

Answer 1

这样就可以了:

from datetime import datetime as dt

# Define the reference date as a datetime object.
date = dt(2020, 12, 5)
# Convert dates to a datatime object for compare.
df['Date'] = pd.to_datetime(df['Date'], format='%d/%m/%Y')

# Apply filters and sum.
df.loc[(df['Tval'] > 0) & (df['Date'] <= date), 'Value'].sum()

输出:

>>> 1257

注意:以上假定国际日期格式 (D/M/Y)。