我可以跨选定的python函数和类方法从一个文件复制到另一个文件吗？

Question

I have a python file that is a collection functions , classes with methods etc. I need to parse it so that I can just extract out the specified functions and classes including the methods that I need for the purpose of over-riding them.

Is there a parser that can parse python code well for this kind of requirement? Will the inbuilt ast module help me?

For example:

Input: Main.py

def f_one():
    """
    """
    pass

class c_one():
    """
    """
    def m_one():
    """
    """
    pass

    def m_two():
    """
    """
    pass
    def m_three():
    """
    """
    pass

class c_two():
    def m_one():
    """
    """
    pass

Goal is to just copy across f_one , c_one and m_one , more generally the code (function, class etc) that I specify.

Output: Copy.py

def f_one():
    """
    """
    pass

class c_one():
    """
    """
    def m_one():
    """
    """
    pass

Answer 1

You just need to import it:

from Main import f_one, c_one

c = c_one()
c.m_two()

Answer 2

You can use inspect.getsource()

import inspect
import Main

objects = [Main.f_one, Main.c_one]

copy = ''

#copy objects
for obj in objects:
    copy += inspect.getsource(obj)
    copy += '\n'

with open('Copy.py', 'w') as out:
    out.write(copy)

This writes the full source code of f_one and c_one to Copy.py. If you only want parts of c_one , you would have to inspect all the members that you want seperately (eg inspect.getsource(Main.c_one.m_one) ) and assemble them manually.

You can also use inspect.getsourcelines() to get an object's source line by line (for instance if you want only the headers).

Note that this is obviously not possible for imports from compiled files.