Python Pandas Concatenate Combinations All Columns Dynamically-CodePudding

COL_A	COL_B	COL_C
PRODUCT_1	UK	1/1/2021

I want to have a table that contains the result

COL_A	COL_B	COL_C	COL_A_COL_B_COL_C	COL_A_COL_B	COL_A_COL_C	COL_B_COL_C
PRODUCT_1	UK	1/1/2021	PRODUCT_1UK1/1/2021	PRODUCT_1UK	PRODUCT_11/1/2021	UK1/1/2021

Basically, combinations concatenated from left to right and place them as new columns in the dataset.

I don't need all of the combinations, so for example, if ABC columns are concatenated, this is enough on that combination (BCA, or ACB are not needed).

How can you do that in Python3 with itertools and pandas? The real table contains more than 10 columns to get their combinations.

CodePudding user response：

You can use pandas.concat:

from itertools import combinations

df.join(pd.concat({a '_' b: df[a] df[b]  for a,b in combinations(df, 2)}, axis=1))

output:

       COL_A COL_B     COL_C  COL_A_COL_B        COL_A_COL_C COL_B_COL_C
0  PRODUCT_1    UK  1/1/2021  PRODUCT_1UK  PRODUCT_11/1/2021  UK1/1/2021

Many combinations:

from itertools import combinations

df.join(pd.concat({'_'.join(x): df[x[0]].str.cat(df[list(x[1:])].astype(str),
                                                 sep='')
                   for i in (2, 3)
                   for x in combinations(df, i)}, axis=1))

output:

       COL_A COL_B     COL_C  COL_A_COL_B        COL_A_COL_C COL_B_COL_C  \
0  PRODUCT_1    UK  1/1/2021  PRODUCT_1UK  PRODUCT_11/1/2021  UK1/1/2021   

     COL_A_COL_B_COL_C  
0  PRODUCT_1UK1/1/2021