您需要
transform:
df['avg_result'] = df.groupby(['a','b'])['result'].transform('mean')这将为您生成groupby值的正确索引列:
a b result avg_result0 1 10 100 1001 1 20 200 2502 1 20 300 2503 2 10 400 4004 2 20 500 5505 2 20 600 550

您需要
transform:
df['avg_result'] = df.groupby(['a','b'])['result'].transform('mean')这将为您生成groupby值的正确索引列:
a b result avg_result0 1 10 100 1001 1 20 200 2502 1 20 300 2503 2 10 400 4004 2 20 500 5505 2 20 600 550