Cross Join in Pandas

Pandas is a neat tool and covers nearly all operations you need for data analysis. However, a cross join feature is missing from the current API.

Although computationally expensive, at times, we need to do a cross join between dataframes, well, at least I needed it recently. So, I quickly hacked a solution and thought maybe I can share here in case it helps someone out there.

  pandas.merge(
    df1.assign(dummy=1),
    df2.assign(dummy=1),
    on='dummy').drop('dummy', axis=1)

Here, we are just assigning a common key column to both the dataframes and then merging them together and finally dropping the dummy common key column that we just created.