Multiplication of column doesn't work as expected pandas

Solution 1:

You forgot to convert to int:

date = data['Date'].str[6:7].astype(int)

Output:

date = data['Date'].str[6:7].astype(int)
stock = data['Total Stock Owned']
data['Incremenet of stock based on month'] = date * stock
print(data)

   Total Stock Owned                 Date  Incremenet of stock based on month
0                  5  1989-02-10 03:45:29                                  10
1                  3  2003-06-17 06:46:02                                  18
2                  8  1982-01-23 12:32:18                                   8
3                  8  2016-04-06 07:29:44                                  32
4                  8  2010-05-29 09:43:25                                  40
5                  8  1982-08-20 11:33:26                                  64
6                  3  1994-04-16 16:21:16                                  12
7                  9  1985-02-21 13:29:34                                  18
8                  8  2005-04-10 03:13:01                                  32
9                  2  1998-03-23 22:31:06                                   6