How to List Imported Modules in Python: sys.modules vs. globals()

Listing Imported Modules in Python

Enlisting all imported modules within a Python script can be useful for various purposes, such as debugging or analyzing dependencies. To achieve this, there are a few approaches to explore.

One straightforward method involves leveraging the sys.modules dictionary. By accessing sys.modules.keys(), you can retrieve a list of strings representing the names of all imported modules. For instance, if you have the following code:

<code class="python">import os
import sys</code>

You can obtain a list of imported modules as follows:

<code class="python">module_names = sys.modules.keys()
print(module_names)</code>

This approach effectively lists all modules imported at the global scope. However, it's worth noting that it does not include modules imported within specific functions or classes within the same script.

For a more comprehensive view that includes locally imported modules, you can inspect the globals() function. This function returns a dictionary of all global variables in the current scope. You can then use this dictionary to identify modules by checking their type using isinstance(val, types.ModuleType).

Here's an example code:

<code class="python">import types

def imports():
    for name, val in globals().items():
        if isinstance(val, types.ModuleType):
            yield val.__name__</code>

Calling the imports() function will iterate over the global variables and yield the names of all imported modules. Keep in mind that this method does not account for local imports or non-module imports such as from x import y.

Overall, by leveraging the sys.modules dictionary or the globals() function, you can effectively enumerate all imported modules in Python, providing flexibility depending on the depth of information you require.

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