upgrading python module within code

问题:

My question relates to this question: Installing python module within code, but involves upgrading the module.

I've tried

packages=['apscheduler','beautifulsoup4','gdata']

def upgrade(packages):
    for package in packages:
        pip.main(['install --upgrade', package])

and

def upgrade(packages):
    for package in packages:
        pip.main(['install', package + ' --upgrade'])

回答1:

Try pip.main(['install', '--upgrade', package]).

"--upgrade" is a separate command-line argument, so you need to pass it separately to main.

回答2:

BrenBarn's answer matches the style of OP's code, but Richard Wheatley's answer is closer to my code.

Richard's answer has a couple of issues I'd like to fix, though, and I didn't want to edit his because the differences are reasonably significant.

from subprocess import call

my_packages = ['apscheduler', 'beautifulsoup4', 'gdata']

def upgrade(package_list):
    call(['pip', 'install', '--upgrade'] + package_list)

Notes:

• No need to import the pip module (subprocess calls the pip binary found in its path)
• Unecessary use of shell=True in call() (and other subprocess functions) should be be avoided, as it puts responsibility on the programmer to protect against shell injection vulnerabilities. (Not really an issue here, but good as a general rule.)
• A single invocation of pip install accepts an arbitrary number of package names, and a single use of --upgrade will apply to all of them.
• We can leverage the previous fact and Python's list concatenation to avoid writing a loop.

回答3:

I now this is an old thread but I have come across it many times and I think I should give another solution since I've used this one. To me this is more user-friendly.

import pip
from subprocess import call

packages=['apscheduler','beautifulsoup4','gdata']

def upgrade(packages):
    for package in packages:
        call("pip install --upgrade " + package, shell=True)

After reading the following Actual meaning of 'shell=True' in subprocess post, it appears that the shell=True command was not needed and is probably not the best idea. import pip is not needed since I do not call pip.main as was seen in some previous answers.

So the new code could be: from subprocess import call

packages=['apscheduler','beautifulsoup4','gdata']

def upgrade(packages):
    for package in packages:
        call("pip install --upgrade " + package)

As for the other answers, I prefer passing the specific string and loop. You will not get a performance hit or gain using either method.