Ipython module not found, but python shell imports correctly?

Why would ipython session not be able to import a module but a python shell session would? Both were executed under the same data_science environment?

 (data_science) C:\Users\ddonovan>python
    Python 3.6.5 | packaged by conda-forge | (default, Apr  6 2018, 16:13:55) [MSC v.1900 64 bit (AMD64)] on win32
    Type "help", "copyright", "credits" or "license" for more information.
    >>> import pandas as pd
    >>> pd.core.common.is_list_like = pd.api.types.is_list_like
    >>> import pandas_datareader.data as web
    >>> exit()

    (data_science) C:\Users\ddonovan>ipython
    Python 3.6.5 |Anaconda, Inc.| (default, Mar 29 2018, 13:32:41) [MSC v.1900 64 bit (AMD64)]
    Type 'copyright', 'credits' or 'license' for more information
    IPython 6.4.0 -- An enhanced Interactive Python. Type '?' for help.

    In [1]: import pandas as pd

    In [2]: pd.core.common.is_list_like = pd.api.types.is_list_like

    In [3]: import pandas_datareader.data as web
    ---------------------------------------------------------------------------
    ModuleNotFoundError                       Traceback (most recent call last)
    <ipython-input-3-bc32bb8bec34> in <module>()
    ----> 1 import pandas_datareader.data as web

    ModuleNotFoundError: No module named 'pandas_datareader'

Solution

I am guessing that you don't have ipython installed into the data_science environment. When you call ipython from the CMD prompt it is defaulting back to the base Anaconda environment and launching from C:\Program Files\anaconda3\Scripts (or wherever the base install is located).

You can check several ways:

Using conda. Run conda list -n data_science ipython from the CMD. If IPython does not appear in the list of installed packaged, you are running from the base environment.

Using where. Run where ipython. If this does not point to a path in the data_science environment, then you are running from the base environment.

Using python. Launch ipython from the CMD, then run

import sys
sys.executable

if the output is not a path to the data_science environment, you are probably running from the base environment.

To solve your issue, use conda to install IPython:

conda install ipython -n data_science