根据Pandas形中其他列的交集连接列中的唯一值

n3ipq98p 于 2023-01-04 发布在其他

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假设我有以下 Dataframe ：

df = pd.DataFrame({"A": ["foo", "foo", "foo", "foo", "foo",
                         "bar", "bar", "bar", "bar","bar"],
                   "B": ["one", "one", "one", "two", "two",
                         "one", "one", "two", "two","two"],
                   "C": ["small", "large", "large", "small",
                         "small", "large", "small", "small",
                         "large", "large"],
                   "D": [1, 2, 3, 4, 5, 6, 7, 8, 9,99999]})

如果“A”、“B”和“C”中的值有交集，我想联接（连接？或合并？）“D”列中的值。所谓交集，我的意思是我想拥有这个DataFrame：

A   B   C   D
0   foo one small   1
1   foo one large   2,3
2   foo two small   4,5
3   bar one large   6
4   bar one small   7
5   bar two small   8
6   bar two large   9,99999

有聚合函数，如最小值，最大值，总和等，但我不能拿出一个解决方案。

pandas

来源：https://stackoverflow.com/questions/74989628/join-unique-values-in-a-column-based-on-intersection-of-other-columns-in-pandas

1条答案

按热度按时间

ffscu2ro1#

将列D转换为字符串，以便可以按join在GroupBy.agg中进行聚合：

df1 = (df.assign(D = df.D.astype(str))
        .groupby(['A','B','C'], sort=False)['D']
        .agg(','.join)
        .reset_index())
print (df1)
     A    B      C        D
0  foo  one  small        1
1  foo  one  large      2,3
2  foo  two  small      4,5
3  bar  one  large        6
4  bar  one  small        7
5  bar  two  small        8
6  bar  two  large  9,99999

或者使用lambda函数：

df1 = (df.groupby(['A','B','C'], sort=False)['D']
        .agg(lambda x: ','.join(x.astype(str)))
        .reset_index())
print (df1)
     A    B      C        D
0  foo  one  small        1
1  foo  one  large      2,3
2  foo  two  small      4,5
3  bar  one  large        6
4  bar  one  small        7
5  bar  two  small        8
6  bar  two  large  9,99999

如果每组D中的值可能重复，并且需要唯一值，则添加DataFrame.drop_duplicates或Series.unique：
一个二个一个一个

赞(0）回复(0）举报 2023-01-04

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根据Pandas形中其他列的交集连接列中的唯一值

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