join row based on column list I would like to make a join between on 3 columns and also on the rows without using pandas.
Anyone have an idea?
listOfToJoin= ['ColA','ColB','ColC']

columns = ['ColA','ColB','ColC','ColD','ColE']
Rows = [[234, 343, 49, 54609, 499], 
        [23, 56, 765, 54609, 432]]


the result should be :
final_Columns = ['ColA_ColB_ColC','ColD','ColE']
final_Rows = [[234_343_49, 54609, 499], 
              [23_56_765, 54609, 432]]
```
for i in range(len(Rows))):
    row = [Rows[i][0] + '_' + Rows[i][1] + '_' + Rows[i][2]]
    row.extend(Rows[i][3:])
    Rows[i] = row