Job Offer: Python Ninja or Pirate!

[Stargaming]

On Tue, 11 Dec 2007 08:57:16 -0800, George Sakkis wrote:

> On Dec 10, 11:07 pm, Stargaming <stargam... at gmail.com> wrote:
>> On Mon, 10 Dec 2007 19:27:43 -0800, George Sakkis wrote:
>> > On Dec 10, 2:11 pm, Stargaming <stargam... at gmail.com> wrote:
[snip]
>> >> Even though I do not qualify for the job, I came up with this
>> >> (<wink>) code (modified list values for demonstration, mixed
>> >> together from previous post and original task):
>>
>> >> print '\n'.join('%s: %d'%(x,len(list(y))) for x,y in __import__
>> >> ('itertools').groupby(sorted(__import__('xml').dom.minidom.parse
>> >> (__import__('urllib').urlopen('http://api.etsy.com/feeds/
>> >> xml_user_details.php?id=%d'%i)).getElementsByTagName('city')
>> >> [0].lastChild.data.title() for i in (71234, 729, 42346, 77290, 729,
>> >> 729))))
>>
[snip]
>>
>> > Alas, it's not:
>>
>> > AttributeError: 'module' object has no attribute 'dom'
[snip]
>> Heh, yes. I did the same error as the participant before me -- test it
>> in a premodified environment. A fix is easy, __import__
>> 'xml.dom.minidom' instead of 'xml'. :-)
> 
> Closer, but still wrong; for some weird reason, __import__ for modules
> in packages returns the top level package by default; you have to use
> the 'fromlist' argument:
> 
>>>> __import__('xml.dom.minidom') is __import__('xml')
> True
> 
>>>> __import__('xml.dom.minidom', fromlist=True)
> <module 'xml.dom.minidom' from '/usr/local/lib/python2.5/xml/dom/
> minidom.pyc'>
> 
> 
> George

No, it's perfectly right::

    >>> __import__('xml.dom.minidom').dom.minidom
    <module 'xml.dom.minidom' from 
    '/usr/lib/python2.5/xml/dom/minidom.pyc'>

You can observe the change pretty well in `sys.modules`::

    >>> __import__('xml')
    <module 'xml' from '/usr/lib/python2.5/xml/__init__.pyc'>
    >>> import sys
    >>> sys.modules.keys()

The result will be a few core modules and the module `xml`. When 
importing `xml.dom.minidom`, though, this imports a lot more files::

    >>> __import__('xml.dom.minidom')
    <module 'xml' from '/usr/lib/python2.5/xml/__init__.pyc'>
    >>> import sys
    >>> sys.modules.keys()

Among them, there are `xml`, `xml.dom` and `xml.dom.minidom`. Having 
these modules imported, `__import__('xml.dom.minidom').dom.minidom` 
becomes a perfectly valid access to the xml/xml.dom packages.

So, your check is correct, importing xml.dom.minidom and xml both give a 
reference to `xml` but the import machinery is invoked to import its 
contents, as well, when explicitly told to.