python - Importing Pandas gives error AttributeError: module 'pandas' has no attribute 'core' in iPython Notebook

Question

I am running a iPython notebook via the Anaconda Navigator app (version 1.1.0). When I want to import pandas it gives me a strange error. I thought the Anaconda app included the pandas package?

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-4-af55e7023913> in <module>()
----> 1 import pandas as pd

/Users/bertcarremans/anaconda/lib/python3.5/site-packages/pandas/__init__.py in <module>()
 37 import pandas.core.config_init
 38 
---> 39 from pandas.core.api import *
 40 from pandas.sparse.api import *
 41 from pandas.stats.api import *

/Users/bertcarremans/anaconda/lib/python3.5/site-packages/pandas/core/api.py in <module>()
  8 from pandas.core.common import isnull, notnull
  9 from pandas.core.categorical import Categorical
---> 10 from pandas.core.groupby import Grouper
 11 from pandas.core.format import set_eng_float_format
 12 from pandas.core.index import (Index, CategoricalIndex, Int64Index,

/Users/bertcarremans/anaconda/lib/python3.5/site-packages/pandas/core/groupby.py in <module>()
 16                               DataError, SpecificationError)
 17 from pandas.core.categorical import Categorical
---> 18 from pandas.core.frame import DataFrame
 19 from pandas.core.generic import NDFrame
 20 from pandas.core.index import (Index, MultiIndex, CategoricalIndex,

/Users/bertcarremans/anaconda/lib/python3.5/site-packages/pandas/core/frame.py in <module>()
 37                                    create_block_manager_from_arrays,
 38                                    create_block_manager_from_blocks)
---> 39 from pandas.core.series import Series
 40 from pandas.core.categorical import Categorical
 41 import pandas.computation.expressions as expressions

/Users/bertcarremans/anaconda/lib/python3.5/site-packages/pandas/core/series.py in <module>()
 33 from pandas.core.internals import SingleBlockManager
 34 from pandas.core.categorical import Categorical, CategoricalAccessor
---> 35 import pandas.core.strings as strings
 36 from pandas.tseries.common import (maybe_to_datetimelike,
 37                                    CombinedDatetimelikeProperties)

AttributeError: module 'pandas' has no attribute 'core'

Answer 1

"Have you tried turning it off and on again?" (Roy of The IT crowd)

This happened to me today, which is why I ended up to this page. Seeing that error was weird since, recently, I have not made any changes in my Python environment. Interestingly, I observed that if I open a new notebook and import pandas I would not get the same error message. So, I did shutdown the troublesome notebook and started it again and voila it is working again!

Even though this solved the problem (at least for me), I cannot readily come up with an explanation as to why it happened in the first place!