inplace for merge pandas code example
Example 1: merge on index pandas
pd.merge(df1, df2, left_index=True, right_index=True)
Example 2: merge dataframe pandas
>>> df1.merge(df2, left_on='lkey', right_on='rkey')
lkey value_x rkey value_y
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7