Pandas: join DataFrames on field with different names?

python pandas join dataframe field
woshitom picture woshitom · Sep 17, 2014 · Viewed 41.4k times · Source

According to this documentation I can only make a join between fields having the same name.

Do you know if it's possible to join two DataFrames on a field having different names?

The equivalent in SQL would be:

SELECT *
FROM df1
LEFT OUTER JOIN df2
  ON df1.id_key = df2.fk_key

Answer

Alex Riley picture Alex Riley · Sep 17, 2014

I think what you want is possible using merge. Pass in the keyword arguments for left_on and right_on to tell Pandas which column(s) from each DataFrame to use as keys:

pandas.merge(df1, df2, how='left', left_on=['id_key'], right_on=['fk_key'])

The documentation describes this in more detail on this page.

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