Return a list of imported Python modules used in a script?

Question

I am writing a program that categorizes a list of Python files by which modules they import. As such I need to scan the collection of .py files ad return a list of which mod

Answer 1

I recently needed all the dependencies for a given python script and I took a different approach than the other answers. I only cared about top level module module names (eg, I wanted foo from import foo.bar).

This is the code using the ast module:

import ast


modules = set()

def visit_Import(node):
    for name in node.names:
        modules.add(name.name.split(".")[0])

def visit_ImportFrom(node):
    # if node.module is missing it's a "from . import ..." statement
    # if level > 0 it's a "from .submodule import ..." statement
    if node.module is not None and node.level == 0:
        modules.add(node.module.split(".")[0])

node_iter = ast.NodeVisitor()
node_iter.visit_Import = visit_Import
node_iter.visit_ImportFrom = visit_ImportFrom

Testing with a python file foo.py that contains:

# foo.py
import sys, os
import foo1
from foo2 import bar
from foo3 import bar as che
import foo4 as boo
import foo5.zoo
from foo6 import *
from . import foo7, foo8
from .foo12 import foo13
from foo9 import foo10, foo11

def do():
    import bar1
    from bar2 import foo
    from bar3 import che as baz

I could get all the modules in foo.py by doing something like this:

with open("foo.py") as f:
    node_iter.visit(ast.parse(f.read()))
print(modules)

which would give me this output:

set(['bar1', 'bar3', 'bar2', 'sys', 'foo9', 'foo4', 'foo5', 'foo6', 'os', 'foo1', 'foo2', 'foo3'])