How to multiply iteratively down a column?

Question

I am having a tough time with this one - not sure why...maybe it\'s the late hour.

I have a dataframe in pandas as follows:

1     10
2     11
3     20
4          


        

Answer 1

Use cumprod.

Example:

df = pd.DataFrame({'A': [10, 11, 20, 5, 10]}, index=range(1, 6))
df['cprod'] = df['A'].cumprod()

Answer 2

Note, since your example is just a single column, a cumulative product can be done succinctly with a Series:

import pandas as pd

s = pd.Series([10, 11, 20, 5, 10])
s

# Output
0    10
1    11
2    20
3     5
4    10
dtype: int64

s.cumprod()

# Output
0        10
1       110
2      2200
3     11000
4    110000
dtype: int64

Kudos to @bananafish for locating the inherent cumprod method.