pandas 没有聚合函数的分组依据
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Group by without an aggregate function
提问by zoran119
I've seen a pandasqlquery like this:
我见过这样的pandasql查询：
df = pd.DataFrame({'A': [1, 2, 2], 'B': [3, 4, 5]})
sqldf('select * from df group by A', locals())
This gives:
这给出：
A B
0 1 3
1 2 6
I find it really weird to have a group by without an aggregate function, but can anyone tell me which function is used on the aggregated columns to reduce multiple values into one?
我发现没有聚合函数的 group by 真的很奇怪，但是谁能告诉我在聚合列上使用哪个函数将多个值减少为一个？
回答by Andrew L
It looks like the groupby method you're looking for is last():
看起来您正在寻找的 groupby 方法是last()：
df = pd.DataFrame({'A': [1, 2, 2], 'B': [3, 4, 5]})
df.groupby('A', as_index=False).last()
Output:
输出：
A B
0 1 3
1 2 5
I'm saying this assuming the 5 was a typo (see my comment above) and meant to be 6.
我说这个假设 5 是一个错字（见我上面的评论）并且是 6。
