如何将 append 列表每次添加到 CSV 文件的新列？

Question

I have a for loop which produces a python list in each of it's iterations. I want to append the list to a new column in the CSV file in each iteration of for loop. The CSV file should be created at the time of writing the first list to it.

The code producing the lists is similar to this code:

for a in range(1,10):
    b = list(range(1,a+1))
    print(b)

After the first iteration of the for loop, the CSV file should contain the first list and so on. The CSV file after three iterations of the for loop should be similar to this.

col1   col2     col3 
1        1        1
2        2        2
3        3        3
         4        4
                  5

I don't necessarily want the headers for the columns. Thank You All...

Answer 1

This might help you:

import pandas as pd
for a in range(1,10):
    b = list(range(1,a+1))
    if a==1:
        df = pd.DataFrame({a:b})    

    else:
        df = df.merge(pd.DataFrame({a:b}), how='outer', left_index=True, right_index=True)

When you print the df you'll get this:

    1   2   3   4   5   6   7   8   9
0   1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1
1   NaN 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2
2   NaN NaN 3.0 3.0 3.0 3.0 3.0 3.0 3
3   NaN NaN NaN 4.0 4.0 4.0 4.0 4.0 4
4   NaN NaN NaN NaN 5.0 5.0 5.0 5.0 5
5   NaN NaN NaN NaN NaN 6.0 6.0 6.0 6
6   NaN NaN NaN NaN NaN NaN 7.0 7.0 7
7   NaN NaN NaN NaN NaN NaN NaN 8.0 8
8   NaN NaN NaN NaN NaN NaN NaN NaN 9