Check if a Debian package is installed from Python

问题

Is there an elegant and more Python-like way to check if a package is installed on Debian?

In a bash script, I'd do:

dpkg -s packagename | grep Status

Suggestions to do the same in a Python script?

回答1:

This is a pythonic way:

import apt
cache = apt.Cache()
if cache['package-name'].is_installed:
    print "YES it's installed"
else:
    print "NO it's NOT installed"

回答2:

If you are checking for the existence of a package that installs a Python module, you can test for this from within a dependent Python script - try to import it and see if you get an exception:

import sys
try:
    import maybe
except ImportError:
    print "Sorry, must install the maybe package to run this program."
    sys.exit(1)

回答3:

A slightly nicer, hopefully idiomatic version of your bash example:

import os, subprocess
devnull = open(os.devnull,"w")
retval = subprocess.call(["dpkg","-s","coreutils"],stdout=devnull,stderr=subprocess.STDOUT)
devnull.close()
if retval != 0:
    print "Package coreutils not installed."

回答4:

This is some code that would give you a neat way to display if the package is installed or not (without triggering a messy error message on the screen). This works in Python 3 only, though.

import apt
cache = apt.Cache()
cache.open()

response = "Package Installed."
try:
    cache['notapkg'].is_installed
except KeyError:
    response = "Package Not Installed."

print(response)

回答5:

Have a look at commands. It's very useful for running things on the command line and getting the status.

Otherwise, I'm sure there is some library that will let you interact with apt. python-apt might work but it's a bit raw. Just capturing the command line seems easier.

回答6:

I needed a cross-platform compatible solution so I ended up using which.

import subprocess
retval = subprocess.call(["which", "packagename"])
if retval != 0:
    print("Packagename not installed!")

Although it's not as pythonic as the above answers it does work on most platforms.

回答7:

Inspired by the previous answers, this works nicely for both Python 2 and Python 3 and avoids try/catch for the key error:

import apt
package = 'foo' # insert your package name here
cache = apt.Cache()
package_installed = False

if package in cache:
    package_installed = cache[package].is_installed

来源：https://stackoverflow.com/questions/3387961/check-if-a-debian-package-is-installed-from-python

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python

debian