On Sat, 09 Oct 2010 12:44:29 -0700, chad wrote:
> Given the following...
>
> [cdal...@localhost oakland]$ python
> Python 2.6.2 (r262:71600, May 3 2009, 17:04:44) [GCC 4.1.1 20061011
> (Red Hat 4.1.1-30)] on linux2 Type "help", "copyright", "credits" or
> "license" for more information.
>>>> class foo:
> ... x = 1
> ... y = 2
> ...
>>>> one = foo()
>>>> two = foo()
>>>> print one
> <__main__.foo instance at 0xb7f3a2ec>
>>>> print two
> <__main__.foo instance at 0xb7f3a16c>
>>>> one.x
> 1
>
>
> Is 'one' a reference or a name space? Also, in 'one.x'. would 'one'
> be the name space?
'one' is a name. Since it is a bound name, it naturally refers to some
object (in this case an instance of foo), which also makes it a reference.
The object that 'one' is bound to is the namespace. The name itself is
not -- the name itself comes *from* a namespace (in this case the global
namespace).
However, since people are lazy, and 98% of the time it makes no
difference, and it is long and tedious to say "the object which the name
'one' is bound to is a namespace", people (including me) will often
shorten that to "'one' is a namespace". But remember that when people use
a name sometimes they're talking about the name itself and sometimes the
object it is bound to:
>>> x = 123 # x applies to the name 'x'.
>>> print x # x applies to the object the name is bound to
123
>>> del x # x applies to the name 'x'
Not all names are references:
>>> spam
Traceback (most recent call last):
File "<stdin>", line 1, in ?
NameError: name 'spam' is not defined
Since the name 'spam' is not bound to any object, it is not a reference.
Likewise, given:
def func(x, y):
pass
the name 'func' is a name which is bound to a function object. The
function object includes two names 'x' and 'y'. Since they're not bound
to anything, they are not references *yet*, but when you call the
function, they become (temporarily) bound.
Hope this helps.
--
Steven
--
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