Jak nainstalovat a importovat moduly Pythonu za běhu?

Pip můžete importovat namísto použití podprocesu:

import pip

def install(package):
    pip.main(['install', package])

# Example
if __name__ == '__main__':
    try:
        import pexpect
    except ImportError:
        install('pexpect')
        import pexpect

Další záběr:

import pip

def import_with_auto_install(package):
    try:
        return __import__(package)
    except ImportError:
        pip.main(['install', package])
    return __import__(package)

# Example
if __name__ == '__main__':
    pexpect = import_with_auto_install('pexpect')
    print(pexpect)

[upravit]

Měli byste zvážit použití souboru requirements.txt spolu s pip. Zdá se, že se snažíte zautomatizovat nasazení (a to je dobře!), ve svém nástrojovém pásu mám také virtualenvwrapper, vagrant a ansible.

Toto je pro mě výstup:

(test)[email protected]:~/test# pip uninstall pexpect
Uninstalling pexpect:
  /usr/lib/python-environments/test/lib/python2.6/site-packages/ANSI.py
  /usr/lib/python-environments/test/lib/python2.6/site-packages/ANSI.pyc
  /usr/lib/python-environments/test/lib/python2.6/site-packages/FSM.py
  /usr/lib/python-environments/test/lib/python2.6/site-packages/FSM.pyc
  /usr/lib/python-environments/test/lib/python2.6/site-packages/fdpexpect.py
  /usr/lib/python-environments/test/lib/python2.6/site-packages/fdpexpect.pyc
  /usr/lib/python-environments/test/lib/python2.6/site-packages/pexpect-2.4-py2.6.egg-info
  /usr/lib/python-environments/test/lib/python2.6/site-packages/pexpect.py
  /usr/lib/python-environments/test/lib/python2.6/site-packages/pexpect.pyc
  /usr/lib/python-environments/test/lib/python2.6/site-packages/pxssh.py
  /usr/lib/python-environments/test/lib/python2.6/site-packages/pxssh.pyc
  /usr/lib/python-environments/test/lib/python2.6/site-packages/screen.py
  /usr/lib/python-environments/test/lib/python2.6/site-packages/screen.pyc
Proceed (y/n)? y
  Successfully uninstalled pexpect
(test)[email protected]:~/test# python test.py
Downloading/unpacking pexpect
  Downloading pexpect-2.4.tar.gz (113Kb): 113Kb downloaded
  Running setup.py egg_info for package pexpect
Installing collected packages: pexpect
  Running setup.py install for pexpect
Successfully installed pexpect
Cleaning up...
<module 'pexpect' from '/usr/lib/python-environments/test/lib/python2.6/site-packages/pexpect.pyc'>
(test)[email protected]:~/test#

Pro ty, kteří používají pip verzi větší než 10.x, neexistuje main funkce pro pip takže alternativním přístupem je použití import pip._internal as pip místo import pip jako :

Aktualizovaná odpověď Paula

import pip._internal as pip

def install(package):
    pip.main(['install', package])

if __name__ == '__main__':
    try:
        import pexpect
    except ImportError:
        install('pexpect')
        import pexpect