how to check each element of dataframe in python code example

Example 1: pandas loop through rows

for index, row in df.iterrows():
    print(row['c1'], row['c2'])

Output: 
   10 100
   11 110
   12 120

Example 2: pandas check if value in column is in a list

df_new[df_new['l_ext'].isin([31, 22, 30, 25, 64])]