pandas 如何根据熊猫中的两列进行分组？
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How to groupby based on two columns in pandas?
提问by ARASH
A similar question might have been asked before, but I couldn't find the exact one fitting to my problem. I want to group by a dataframe based on two columns. For exmaple to make this
之前可能有人问过类似的问题，但我找不到适合我的问题的确切问题。我想根据基于两列的数据框进行分组。例如，使这个
id product quantity
1 A 2
1 A 3
1 B 2
2 A 1
2 B 1
3 B 2
3 B 1
Into this:
进入这个：
id product quantity
1 A 5
1 B 2
2 A 1
2 B 1
3 B 3
Meaning that summation on "quantity" column for same "id" and same "product".
这意味着相同“id”和相同“产品”的“数量”列的总和。
回答by jezrael
You need groupbywith parameter as_index=Falsefor return DataFrameand aggregating mean:
您需要返回和聚合groupby参数：as_index=FalseDataFramemean
df = df.groupby(['id','product'], as_index=False)['quantity'].sum()
print (df)
id product quantity
0 1 A 5
1 1 B 2
2 2 A 1
3 2 B 1
4 3 B 3
Or add reset_index:
或添加reset_index：
df = df.groupby(['id','product'])['quantity'].sum().reset_index()
print (df)
id product quantity
0 1 A 5
1 1 B 2
2 2 A 1
3 2 B 1
4 3 B 3
回答by piRSquared
You can use pivot_tablewith aggfunc='sum'
你可以用pivot_table与aggfunc='sum'
df.pivot_table('quantity', ['id', 'product'], aggfunc='sum').reset_index()
id product quantity
0 1 A 5
1 1 B 2
2 2 A 1
3 2 B 1
4 3 B 3
回答by Shubham R
You can use groupbyand aggregatefunction
您可以使用groupby和aggregate功能
import pandas as pd
df = pd.DataFrame({
'id': [1,1,1,2,2,3,3],
'product': ['A','A','B','A','B','B','B'],
'quantity': [2,3,2,1,1,2,1]
})
print df
id product quantity
0 1 A 2
1 1 A 3
2 1 B 2
3 2 A 1
4 2 B 1
5 3 B 2
6 3 B 1
df = df.groupby(['id','product']).agg({'quantity':'sum'}).reset_index()
print df
id product quantity
0 1 A 5
1 1 B 2
2 2 A 1
3 2 B 1
4 3 B 3
