在数据框中生成7列的所有组合，并添加相应的行以生成新的列 [英] Generating all the combinations of 7 columns in a dataframe and add the corresponding rows to generate new columns

问题描述

我有一个与下面类似的数据框:

I have a dataframe that looks similar to below:

Wave    A    B   C
340    77   70  15
341    80   73  15
342    83   76  16
343    86   78  17

我想生成将包含现有列的所有可能组合的列.我在这里显示了3个列，但在我的实际数据中，我有7列，因此共有127种组合.所需的输出如下:

I want to generate columns that will have all the possible combinations of the existing columns. I showed 3 cols here but in my actual data, I have 7 columns and therefore 127 total combinations. The desired output is as follows:

Wave    A    B   C   AB   AC   AD   BC ... ABC
340    77   70  15   147  92   ...
341    80   73  15   153  95   ... 
342    83   76  16   159  99   ...

我实现了一个效率很低的版本，用户输入组合(AB，AC等)，并使用行的总和创建一个新的col.对于127种组合(尤其是具有描述性的列名)，这似乎几乎是不可能的.

I implemented a quite inefficient version where the user inputs the combinations (AB, AC, etc.) and a new col is created with the sum of the rows. This seems almost impossible to accomplish for 127 combinations, esp with descriptive col names.

推荐答案

从itertools中创建包含 chain + combinations 的所有组合的列表，然后对相应的列求和:

Create a list of all combinations with chain + combinations from itertools, then sum the appropriate columns:

from itertools import combinations, chain

cols = [*df.iloc[:,1:]]
l = list(chain.from_iterable(combinations(cols, n+2) for n in range(len(cols))))
#[('A', 'B'), ('A', 'C'), ('B', 'C'), ('A', 'B', 'C')]

for items in l:
    df[''.join(items)] = df.loc[:, items].sum(1)

   Wave   A   B   C   AB   AC  BC  ABC
0   340  77  70  15  147   92  85  162
1   341  80  73  15  153   95  88  168
2   342  83  76  16  159   99  92  175
3   343  86  78  17  164  103  95  181

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