Combining two dataframes in pandas

Asked Aug 04 '17 at 16:24

Active Aug 04 '17 at 16:53

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I tried combining two dataframess with one having less rows and than the other like Column1 is in 1st dataframe and Column 2 is in 2nd dataframe -

Column 1  Column 2
  A             a
  B             b
                 c
                 d

what I wanted to do was 8 rows in total after combining with rows mapped as (this is a new dataframe) -

A a
A b
A c
A d
B a
B b
B c
B d

I searched for joins and concat and merge but I wasn't able to accomplish this. Any help please, thanks. I'm really very sorry for bad formatting.

edited Aug 04 '17 at 16:53

asked Aug 04 '17 at 16:24

1

You probably need an outer join but please improve your sample by adding headers/indices and some additional columns. – ayhan Aug 04 '17 at 16:28
Now if you could help? – NoSuchUserException Aug 04 '17 at 16:58
`df1.assign(key=1).merge(df2.assign(key=1)).drop('key', axis=1)` credit goes to [@Matti John](https://stackoverflow.com/a/13270110/2285236) – ayhan Aug 04 '17 at 17:06
Great thanks a lot – NoSuchUserException Aug 04 '17 at 17:13
How does this work exactly? – NoSuchUserException Aug 04 '17 at 17:17
The assign part adds a constant value to both DataFrames in the key column. Merge starts traversing the first DataFrame on the key column. In the first row it sees the value 1 and looks at the other DataFrame if it can match that value. It sees the first row matches, so it brings it. It sees the second one also matches, brings that too. Does that for all the rows in the second DataFrame and then it repeats for all the rows in the first DataFrame. – ayhan Aug 04 '17 at 17:20
Is there a way with concat? – NoSuchUserException Aug 04 '17 at 17:25

0 Answers0