newbie: loop, modify dataframe cells

[jefsummers]

This creates a dataframe, loops through and prints the values, and if the value is 6 it is modified to 100.

import pandas as pd
df = pd.DataFrame(({1,2,3},{4,5,6},{7,8,9}))
for row in range(3) :
    for col in range(3) :
        print(df.iloc[row,col])
        if df.iloc[row,col] == 6 :
            df.iloc[row,col] = 100
df