This will take care of merging - without sorting
Talking of your code
pandas.merge(source1, source2, how='outer', right_index=True, left_index=True)
Talking of your code
iois a name of a standard module (and 2-letter names are not much better than 1 letter)
- The error message explains exactly what your problem is. You may look at
list.extend
Test everything in a Python shell (iPython, Azure Notebook, etc.)
- Someone gave you an advice you liked? Test it - maybe the advice was actually bad.
- Someone gave you an advice you think is bad? Test it before arguing - maybe it was good.
- You posted a claim that something you did not test works? Be prepared to eat your hat.