Can hasattr work on a Module?

Question

I'm adding dynamically attribute to a module, before using it I want to verify that the added attribute exist (in the module).

hasattr signature is:

hasattr(object, name)

module is not an object, so how can I verify the existence of the added attribute ?

Thanks for your answer. I need some key word for the module name. If for example my module is called 'MyModule' and I want to see if attribute 'MyAttribute' is exist, I want NOT to check it by hasattr('MyModule', 'MyAttribute') but by some key word that will recognize the module name - hasattr(key word, 'MyAttribute'). — EitanG, Oct 22 '13 at 08:00

Martijn Pieters · Accepted Answer · 2013-10-22T08:44:01.967

11

A Python module is an object. hasattr() works just fine on that.

Demo:

>>> import os
>>> type(os)
<type 'module'>
>>> os
<module 'os' from '/Users/mj/Development/venvs/stackoverflow-2.7/lib/python2.7/os.pyc'>
>>> hasattr(os, 'sep')
True
>>> hasattr(os, 'foobar')
False

If you have a string with the module name, then you can look up the module object in the sys.modules mapping:

>>> import sys
>>> sys.modules['os']
<module 'os' from '/Users/mj/Development/venvs/stackoverflow-2.7/lib/python2.7/os.pyc'>
 >>> hasattr(sys.modules['os'], 'sep')
True

edited Oct 22 '13 at 08:44

answered Oct 22 '13 at 07:36

Martijn Pieters

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Thanks for your answer. I need some key word for the module name. If for example my module is called 'MyModule' and I want to see if attribute 'MyAttribute' is exist, I want NOT to check it by hasattr('MyModule', 'MyAttribute') but by some key word that will recognize the module name - hasattr(key word, 'MyAttribute'). – EitanG Oct 22 '13 at 07:43
@EitanG: You can look up modules by name in the `sys.modules` mapping: `hasattr(sys.modules[modulename], 'MyAttribute')`. – Martijn Pieters Oct 22 '13 at 08:40

score 2 · Answer 2 · answered Oct 22 '13 at 07:37

2

>>> import os
>>> hasattr(os, 'path')
True
>>>

As you seen hasattr works on modules (everything is an object in python, including functions and modules).

answered Oct 22 '13 at 07:37

sloth

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score 1 · Answer 3 · answered Oct 22 '13 at 07:41

1

Why not?

>>> import sys

>>> sys.modules['sys']
<module 'sys' (built-in)>

>>> type(sys.modules['sys'])
<type 'module'>

>>> hasattr(sys, 'argv')
True

answered Oct 22 '13 at 07:41

alko

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score 0 · Answer 4 · edited May 23 '17 at 11:53

0

Actually, it is an object. Everything in python is an object. Look at this question as well.

    >>>import os
    >>>issubclass(type(os), object)
    True
    >>>hasattr(os, 'kill')
    True
    >>>

edited May 23 '17 at 11:53

Community

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answered Oct 22 '13 at 07:38

Alexander Zhukov

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Can hasattr work on a Module?

4 Answers4