Answers for "how to merge df in python"

pandas left join

df.merge(df2, left_on = "doc_id", right_on = "doc_num", how = "left")

join tables pandas

In [99]: result = left.join(right, on=['key1', 'key2'], how='inner')

merge two df

bigdata = pd.concat([data1, data2], ignore_index=True, sort=False)

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