[three]Bean

dynamically copying methods and properties from one class to another (in python)

Jan 27, 2011 | categories: python View Comments

Here's a little generalization on the previous post on reassigning methods.

#!/usr/bin/python

import warnings
import types

class Foo(object):
    def __init__(self, id):
        self.id = id

    def bar(self):
        print self.id

    @property
    def baz(self):
        print self.id

class Oof(object):
    def __init__(self, id):
        self.id = id

def copy_methods_and_properties(cls1, cls2):
    for attr in dir(cls1):
        fattr = getattr(cls1, attr)

        # only copy methods and properties
        if type(fattr) not in [types.UnboundMethodType, property]:
            continue

        # Don't erase methods that cls2 already has
        if hasattr(cls2, attr):
            continue

        if isinstance(fattr, property):
            setattr(cls2, attr, property(fattr.fget, fattr.fset, fattr.fdel))
        elif isinstance(fattr, types.UnboundMethodType):
            setattr(cls2, attr, fattr.__func__)

    return cls2


if __name__ == '__main__':
    Oof = copy_methods_and_properties(Foo, Oof)

    f = Foo(52)
    o = Oof(10)

    f.bar()
    o.bar()

    f.baz
    o.baz

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