Pandas/Python:如何连接两个没有重复的数据帧?

2022-01-10 00:00:00 python pandas duplicates

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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