python - How to list imported modules?

Question

How to enumerate all imported modules?

E.g. I would like to get ['os', 'sys'] from this code:

import os
import sys

Answer 1

import sys
sys.modules.keys()

An approximation of getting all imports for the current module only would be to inspect globals() for modules:

import types
def imports():
    for name, val in globals().items():
        if isinstance(val, types.ModuleType):
            yield val.__name__

This won't return local imports, or non-module imports like from x import y. Note that this returns val.__name__ so you get the original module name if you used import module as alias; yield name instead if you want the alias.

Answer 2

Find the intersection of sys.modules with globals:

import sys
modulenames = set(sys.modules) & set(globals())
allmodules = [sys.modules[name] for name in modulenames]

Answer 3

If you want to do this from outside the script:

Python 2

from modulefinder import ModuleFinder
finder = ModuleFinder()
finder.run_script("myscript.py")
for name, mod in finder.modules.iteritems():
    print name

Python 3

from modulefinder import ModuleFinder
finder = ModuleFinder()
finder.run_script("myscript.py")
for name, mod in finder.modules.items():
    print(name)

This will print all modules loaded by myscript.py.

Answer 4

print [key for key in locals().keys()
       if isinstance(locals()[key], type(sys)) and not key.startswith('__')]

Answer 5

let say you've imported math and re:

>>import math,re

now to see the same use

>>print(dir())

If you run it before the import and after the import, one can see the difference.

Answer 6

It's actually working quite good with:

import sys
mods = [m.__name__ for m in sys.modules.values() if m]

This will create a list with importable module names.

Answer 7

This code lists modules imported by your module:

import sys
before = [str(m) for m in sys.modules]
import my_module
after = [str(m) for m in sys.modules]
print [m for m in after if not m in before]

It should be useful if you want to know what external modules to install on a new system to run your code, without the need to try again and again.

It won't list the sys module or modules imported from it.

Answer 8

Stealing from @Lila (couldn't make a comment because of no formatting), this shows the module's /path/, as well:

#!/usr/bin/env python
import sys
from modulefinder import ModuleFinder
finder = ModuleFinder()
# Pass the name of the python file of interest
finder.run_script(sys.argv[1])
# This is what's different from @Lila's script
finder.report()

which produces:

Name                      File
----                      ----

...
m token                     /opt/rh/rh-python35/root/usr/lib64/python3.5/token.py
m tokenize                  /opt/rh/rh-python35/root/usr/lib64/python3.5/tokenize.py
m traceback                 /opt/rh/rh-python35/root/usr/lib64/python3.5/traceback.py
...

.. suitable for grepping or what have you. Be warned, it's long!

Answer 9

I like using a list comprehension in this case:

>>> [w for w in dir() if w == 'datetime' or w == 'sqlite3']
['datetime', 'sqlite3']

# To count modules of interest...
>>> count = [w for w in dir() if w == 'datetime' or w == 'sqlite3']
>>> len(count)
2

# To count all installed modules...
>>> count = dir()
>>> len(count)