change nan pandas code example

Example 1: replace nan in pandas

df['DataFrame Column'] = df['DataFrame Column'].fillna(0)

Example 2: how to replace nan with 0 in pandas

df['product']=df['product'].fillna(0)
df['context']=df['context'].fillna(0)
df

Example 3: pandas replace empty string with nan

df = df.replace(r'^\s*$', np.NaN, regex=True)