pandas dataframe add column based on another code example

Example 1: append one column pandas dataframe

df1 = df1.join(df2[column])

Example 2: Adding a new column in pandas dataframe from another dataframe with different index

merge(left, right, how='left', on=None, left_on=None, right_on=None,
      left_index=False, right_index=False, sort=True,
      suffixes=('_x', '_y'), copy=True)