how to replace nan in pandas code example

Example 1: replace nan in pandas

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

Example 2: dataframe fillna with 0

df['column'] = df['column'].fillna(0)

Example 3: pandas where retuning NaN

# Try using a loc instead of a where:
df_sub = df.loc[df.yourcolumn == 'yourvalue']