如何找到过时的python模块？

Question

I have written a program in python 3.3 and I am using WinPython and Inno to make a portable python installation. However, there are a lot of modules in the WinPython installation that I do not really need in my program. Is there a way to find all modules of a python installation that are not used by a random script?

Example: Lets say I have installed numpy and matplotlib and my program does this:

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0,2*np.pi,100)
y = np.sin(x)

plt.plot(x,y)
plt.show()

I want to delete all files in the python installation, that are not needed to run this program.

Answer 1

A cheat's way might be to leverage the creation of pyc files at runtime.

1. remove all .pyc files from WinPython
2. ensure you have permission to make .pyc files in the WinPython folder when the program runs
3. run the program

At the end, pyc files should only have been generated for modules (.py files) that were used at runtime. So any file which does not have a corresponding .pyc can be excluded.

Note however, that this will not catch compiled (.so) modules.

Alternatively, and a slightly more robust method, would be to use a PathFinder or more generic Finder . By hooking into the import mechanism, you can intercept calls Python makes to find modules that are being imported. You can use this to log information about the modules (and so .py files) used.

class MyFinder(importlib.machinery.PathFinder):
    @classmethod
    def find_module(self, fullname, path=None):
        # do some logging of the module being imported, and where it is coming from.