Python __builtins__中缺少__import__（在Django Shell中）

Question

I hope this isn't too dumb of a question :-( but why isn't __import__ included in inspect.getmembers(__builtins__) ?

Here's what I get when I try to print the builtins:

>>> sorted([name for (name,obj) in inspect.getmembers(__builtins__)])
['__class__', '__cmp__', '__contains__', '__delattr__', '__delitem__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'clear', 'copy', 'fromkeys', 'get', 'has_key', 'items', 'iteritems', 'iterkeys', 'itervalues', 'keys', 'pop', 'popitem', 'setdefault', 'update', 'values', 'viewitems', 'viewkeys', 'viewvalues']

Update:

Actually I was in the Django 1.6 shell when I ran that. (Python 2.7).

Running it in Python 2.7 alone does include __import__ . What could be going on?

Answer 1

From the docs:

27.3. __builtin__ — Built-in objects

CPython implementation detail: Most modules have the name __builtins__ (note the 's' ) made available as part of their globals. The value of __builtins__ is normally either this module or the value of this modules's [sic] __dict__ attribute. Since this is an implementation detail, it may not be used by alternate implementations of Python.

In your case, it looks like the __builtins__ you are looking at is the dictionary not the module ( __builtin__.__dict__ rather than __builtin__ ). So inspect.getmembers is returning the attributes of the dict class rather than the keys. Instead you might want something like the following:

if isinstance(__builtins__, dict):
    names = sorted(__builtins__)
else:
    names = sorted(name for name, obj in inspect.getmembers(__builtins__))

Or alternatively:

import __builtin__
names = sorted(name for name, obj in inspect.getmembers(__builtin__))