如何安装特定 python package 的所有依赖项？

Question

When I install some python packages, pandas for example, I'd like to use the following command:

conda install pandas

This does install some denpendencies of pandas , BUT NOT ALL!

When I run the following code:

import pandas as pd

df = pd.DataFrame()
df.to_excel('a_excel_file.xlsx')

It gives me errors:

Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "D:\Miniconda\envs\to_be_deleted2\lib\site-packages\pandas\core\generic.py", line 2181, in to_excel
    engine=engine,
  File "D:\Miniconda\envs\to_be_deleted2\lib\site-packages\pandas\io\formats\excel.py", line 726, in write
    writer = ExcelWriter(stringify_path(writer), engine=engine)
  File "D:\Miniconda\envs\to_be_deleted2\lib\site-packages\pandas\io\excel\_openpyxl.py", line 18, in __init__
    from openpyxl.workbook import Workbook
  File "D:\PyCharm Professional 2019.1.3\helpers\pydev\_pydev_bundle\pydev_import_hook.py", line 21, in do_import
    module = self._system_import(name, *args, **kwargs)
ModuleNotFoundError: No module named 'openpyxl'

Looks like openpyxl were not installed as the installation of pandas . Why that happended? How to fix it?

Answer 1

openpyxl is an optional dependency of pandas , this is the reason why it wasn't installed when you installed pandas .

pandas has many such optional dependencies which add useful, but not core, features - see the installation documentation for a complete list.