pandas replace value searching by other column code example

Example 1: replacing values in pandas dataframe

df['coloum'] = df['coloum'].replace(['value_1','valu_2'],'new_value')

Example 2: replace value of dataframe with another column

df['col1'] = np.where(df['col1'] == 0, df['col2'], df['col1'])
df['col1'] = np.where(df['col1'] == 0, df['col3'], df['col1'])