Python：在 for 循环中创建新列名

Question

I am trying to make custom column header names for the dataframe using a for loop. Currently I am using two for loops to iterate through a dataframe, but don't know how to put new column headers in without hardcoding them. I have

df = pandas.DataFrame({
     'A':[5,3,6,9,2,4],
     'B':[4,5,4,5,5,4],
     'C':[7,8,9,4,2,3],
     'D':[1,3,5,7,1,0],})

result = []
for i in range(len(df.columns)):
         SelectedCol = (df.iloc[:,i])
         for c in range(i+1, len(df.columns)):
                result.append(((SelectedCol+1)/ (df.iloc[:,c]+1)))
            
df1 = pandas.DataFrame(result)
df1=df1.transpose()

In df, the first column is taken and multiplied to the second, third, and fourth. And then the code takes the second, and multiples it by the third and fourth, and continues in the for loop so the output columns are 'A B', 'A C', 'A D', 'B C', 'B D', and 'C D'.

What could I add to my for loop to extract the column names so each column name of df1 can be 'Long A, Short B', 'Long A, Short C'.... and finally 'Long C, Short D'

Thanks for your help

Answer 1

from itertools import combinations
for x,y in combinations(df.columns,2):
    df['Long '+x+' Short '+y]=df[x]*df[y]

Answer 2

import pandas
from itertools import combinations
df = pandas.DataFrame({
    'A': [5, 3, 6, 9, 2, 4],
    'B': [4, 5, 4, 5, 5, 4],
    'C': [7, 8, 9, 4, 2, 3],
    'D': [1, 3, 5, 7, 1, 0], })
# get all col name
for index, row in df.iteritems():
    print(index)
# get all  combinations
result = combinations(df.iteritems(), 2)
# calc
for name, data in result:
    _name = name[0] + data[0]
    _data = name[1] * data[1]
    df[_name] = _data
print(df)

A
B
C
D
   A  B  C  D  AB  AC  AD  BC  BD  CD
0  5  4  7  1  20  35   5  28   4   7
1  3  5  8  3  15  24   9  40  15  24
2  6  4  9  5  24  54  30  36  20  45
3  9  5  4  7  45  36  63  20  35  28
4  2  5  2  1  10   4   2  10   5   2
5  4  4  3  0  16  12   0  12   0   0