regex to parse import statements in python

Question

can someone help me writing single regex to get module(s) from python source line?

from abc.lmn import pqr
from abc.lmn import pqr as xyz
import abc
import abc as xyz

it has 3 sub parts in it

[from(s)<module>(s)] --> get module if this part exist
import(s)<module>     --> get module
[(s)as(s)<alias>]    --> ignore if this part exist

something like this

:?[from(s)<module>(s)]import(s)<module>:?[(s)as(s)<alias>]

Answer 1

Instead of using a regex, using the built in python library ast might be a better approach. https://docs.python.org/2/library/ast.html You can use it to parse python syntax.

import ast

import_string = """from abc.lmn import pqr
from abc.lmn import pqr as xyz
import abc
import abc as xyz"""

modules = []
for node in ast.iter_child_nodes(ast.parse(import_string)):
    if isinstance(node, ast.ImportFrom):
        if not node.names[0].asname:  # excluding the 'as' part of import
            modules.append(node.module)
    elif isinstance(node, ast.Import): # excluding the 'as' part of import
        if not node.names[0].asname:
            modules.append(node.names[0].name)

that will give you ['abc.lmn', 'abc'] and it is fairly easy to tweak if you want to pull other information.