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Question

I'm trying to install automatically each library in python if it isn't installed.

#!/usr/bin/python
# -*- coding: utf-8 -*-

from pip._internal import main
pkgs = ['Bio==0.1.0','argparse==1.4.0']
for package in pkgs:
    try:
        import package
    except ImportError:
        main(['install', package])

But, this error occurs:

Collecting Bio==0.1.0
Using cached https://files.pythonhosted.org/packages/14/c2/43663d53b93ef7b4d42cd3550631552887f36db02c0150d803c69ba636a6/bio-0.1.0-py2.py3-none-any.whl 
Installing collected packages: Bio 
Successfully installed Bio-0.1.0 
Collecting argparse==1.4.0   
Using cached https://files.pythonhosted.org/packages/f2/94/3af39d34be01a24a6e65433d19e107099374224905f1e0cc6bbe1fd22a2f/argparse-1.4.0-py2.py3-none-any.whl 
ERROR: Could not install packages due to an EnvironmentError: [Errno2] No such file or directory: '/tmp/pip-req-tracker-6sqtap8q/139713c65f8ac559a034717470dc5a6e30a6db86bdc3d69fe2bc0e63'

I notice that this occur always after the first library installation, eg: If I change ['Bio','argparse'] for ['argparse','Bio'] , then argparse will be installed, but Bio will not.

Answer 1

Do not do this.

Instead:

• either actually package your Python project properly with accurate dependencies (look up setuptools , poetry , flit , or any other similar project);

• or instruct your users to install your project's dependencies themselves, you can facilitate this by providing a pip -compatible requirements.txt file .

Additional note here is how to "Using pip from your program" .