how to do a continuous sum with python pandas-CodePudding

I would like to do the same in python pandas as shown on the picture. enter image description here

This is sum function where the first cell is fixed and the formula calculates "continuous sum".

I tried to create pandas data frame however I did not manage to do this exactly.

CodePudding user response：

You can use DataFrame.cumsum() to achieve what you want: import pandas as pd


df = pd.DataFrame([10, 20, 30])
print(df.cumsum())

CodePudding user response：

Based on the example you shared, use pandas.Series.cumsum with pandas.Series.ffill :

import pandas as pd
import numpy as np

df= pd.DataFrame({'Nuber': [10.0, np.NaN, 20.0, np.NaN, np.NaN, 10.0, np.NaN, np.NaN, 30.0]})

df["Sum cont"]= df["Nuber"].cumsum().ffill()

# Output :

print(df)

   Nuber  Sum cont
0   10.0      10.0
1    NaN      10.0
2   20.0      30.0
3    NaN      30.0
4    NaN      30.0
5   10.0      40.0
6    NaN      40.0
7    NaN      40.0
8   30.0      70.0

CodePudding user response：

I would refer to pandas cumsum() For example:

df['NEW_COLUMN_CUMULATED'] = df['OLD_COLUMN'].cumsum()