How to print rolling window equation process from pandas dataframe in python?

Question

I created a pandas dataframe sample and it tried to sum for every 3 rows:

import pandas as pd
import numpy as np

d={\'A\':[100,110,120,175,164,169,155,153,156,20         


        

Answer 1

d={'A':[100,110,120,175,164,169,155,153,156,200]}
df=pd.DataFrame(d)
for ind in df.index:
        if ind == 0 or ind == 1:
            print("NaN")
        else:
            sumOf3Numbers = df["A"][ind-2]+df["A"][ind-1]+df["A"][ind]
            print("{}={}+{}+{}".format(sumOf3Numbers,df["A"][ind-2],df["A"][ind-1],df["A"][ind]))