Pandas/Python:如何连接两个没有重复的数据帧?
问题描述
我想将两个数据帧 A、B 连接到一个没有重复行的新数据帧(如果 B 中的行已经存在于 A 中,则不要添加):
I'd like to concatenate two dataframes A, B to a new one without duplicate rows (if rows in B already exist in A, don't add):
数据框 A:数据框 B:
Dataframe A: Dataframe B:
I II I II
0 1 2 5 6
1 3 1 3 1
新数据框:
I II
0 1 2
1 3 1
2 5 6
我该怎么做?
解决方案
最简单的方法是只进行连接,然后删除重复项.
The simplest way is to just do the concatenation, and then drop duplicates.
>>> df1
A B
0 1 2
1 3 1
>>> df2
A B
0 5 6
1 3 1
>>> pandas.concat([df1,df2]).drop_duplicates().reset_index(drop=True)
A B
0 1 2
1 3 1
2 5 6
reset_index(drop=True)
是修复concat()
和drop_duplicates()
之后的索引.没有它,您将拥有 [0,1,0]
的索引,而不是 [0,1,2]
.如果不立即重置,这可能会导致对该 dataframe
的进一步操作出现问题.
The reset_index(drop=True)
is to fix up the index after the concat()
and drop_duplicates()
. Without it you will have an index of [0,1,0]
instead of [0,1,2]
. This could cause problems for further operations on this dataframe
down the road if it isn't reset right away.
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