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#Display the missing values using "ISNULL" function
# subject wise marks for 4 students
data_science_a = {'DAA':[90, 97, np.nan, 91],
'DBMS': [80, 85, 86, np.nan],
'Java':[np.nan, 78, 82, np.nan],
'Python':[88, np.nan,89,79]}
# creating a dataframe from the above list
df = pd.DataFrame(data_science_a)
#Display the Null values in the dataframe using isnull
df.isnull()