Pandas Import : ModuleNotFoundError: No module named 'pandas._libs.tslib'

Question

Whenever I try to import pandas, whether inside a virtualenv or otherwise I am always getting this error.

Python 3.6.2 |Anaconda custom (64-bit)| (default, Sep 19 2017, 08:03:39) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import pandas as pd
Traceback (most recent call last):
  File "C:\Users\ishan\AppData\Roaming\Python\Python36\site-packages\pandas\__init__.py", line 26, in <module>
from pandas._libs import (hashtable as _hashtable,
  File "C:\Users\ishan\AppData\Roaming\Python\Python36\site-packages\pandas\_libs\__init__.py", line 3, in <module>
from .tslib import iNaT, NaT, Timestamp, Timedelta, OutOfBoundsDatetime
ModuleNotFoundError: No module named 'pandas._libs.tslib'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\ishan\AppData\Roaming\Python\Python36\site-packages\pandas\__init__.py", line 35, in <module>
"the C extensions first.".format(module))
ImportError: C extension: No module named 'pandas._libs.tslib' not built. If you want to import pandas from the source directory, you may need to run 'python setup.py build_ext --inplace --force' to build the C extensions first.

I tried the follwoing solutions:

1. Cloning pandas from git and running SETUP.py (on an instance of python 3.6 installed directly into my win10 os)
2. Using anaconda as python distribution and conda to install pandas
3. Updating microsoft visual c++ 2017 redistributable
4. Updating C:\ProgramData\Anaconda3\Lib\site-packages\PyInstaller\hooks\hook-pandas.py

None of these seem to work. Please help me understand what the issue here is.

Answer 1

This exception:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\ishan\AppData\Roaming\Python\Python36\site-packages\pandas\__init__.py", line 35, in <module>
"the C extensions first.".format(module))
ImportError: C extension: No module named 'pandas._libs.tslib' not built. If you want to import pandas from the source directory, you may need to run 'python setup.py build_ext --inplace --force' to build the C extensions first

suggests that pandas was not built properly during installation.

The latter sentence:

If you want to import pandas from the source directory, you may need to run python setup.py build_ext --inplace --force to build the C extensions first

Is really only something you ought to be doing if you are contributing to pandas source code (e.g. to fix a pandas bug or add a feature to pandas itself) to the pandas-dev github repository*.
Most likely you shouldn't be building from source in your project.

Generally anaconda is pretty good at installing pandas correctly, and so my guess/comment was:

My guess is the virtual env is not using anaconda, and the install of pandas is messed up (perhaps created before installing anaconda?). I would delete this directory C:\Users\ishan\AppData\Roaming\Python\Python36 and see if that helps

The reason I suggested that directory was because it was in the error message AND it doesn't look like somewhere I expect anaconda's installation of pandas to be (either generally or as a virtualenv).

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* Note: this is something fun to do, to give back to the pandas community: there's some low-hanging fruit, typos or code changes, so I recommend investigating whether there's any way you can contribute.