# Write a program in Python to perform average of rolling window size 3 calculation in a given dataframe

Assume, you have a dataframe and the result for rolling window size 3 calculation is,

Average of rolling window is:
Id Age  Mark
0 NaN NaN  NaN
1 1.5 12.0 85.0
2 2.5 13.0 80.0
3 3.5 13.5 82.5
4 4.5 31.5 90.0
5 5.5 60.0 87.5

To solve this, we will follow the below approach −

## Solution

• Define a dataframe

• Apply df.rolling(window=2).mean() to calculate average of rolling window size 3 is

df.rolling(window=2).mean()

### Example

Let’s check the following code to get a better understanding −

import pandas as pd
df = pd.DataFrame({"Id":[1, 2, 3, 4, 5,6],
"Age":[12, 12, 14, 13, 50,70],
"Mark":[80, 90, 70, 95, 85,90],
})
print("Dataframe is:\n",df)
print("Average of rolling window is:\n",df.rolling(window=2).mean())

### Output

Dataframe is:
Id Age Mark
0 1 12  80
1 2 12  90
2 3 14  70
3 4 13  95
4 5 50  85
5 6 70  90
Average of rolling window is:
Id Age Mark
0 NaN  NaN  NaN
1 1.5 12.0 85.0
2 2.5 13.0 80.0
3 3.5 13.5 82.5
4 4.5 31.5 90.0
5 5.5 60.0 87.5