[FIXED] unique indexes throwing: Reindexing only valid with uniquely valued Index objects

Issue

So I have a list of DataFrames. When trying to append them I get:

pandas.errors.InvalidIndexError: Reindexing only valid
with uniquely valued Index objects

However, my indexes are unique, example:

dfList[0].index
Index(['5560654070'], dtype='object')

fList[1].index
Index(['5562221068'], dtype='object')

When append(), or concat(), both give the error above.

dfList[0].append(dfList[1])

"""
pandas.errors.InvalidIndexError: Reindexing only valid with uniquely valued Index objects
"""

I have tried reset_index() as well as ignore_index=True, but nothing seems to work.

Solution

Found the reason for the errors. As somewhat of a pandas noob I thought the error only had to do with the index. However the problem was that I had duplicate columns in each DataFrame.

Answered By - henaxe