learning python ...

[Cameron Simpson]

On 25May2021 06:08, hw <hw at adminart.net> wrote:
>On 5/25/21 12:37 AM, Greg Ewing wrote:
>>If you rebind a name, and it held the last reference to an
>>object, there is no way to get that object back.
>
>Are all names references?

Yes.

>When I pass a name as a parameter to a function, does the object the 
>name is referring to, when altered by the function, still appear 
>altered after the function has returned?  I wouldn't expect that ...

Yes. Please ready the language specification. This is basic to Python's 
function.

>>On the other hand, if you shadow a name, the original name
>>still exists, and there is usually some way to get at it,
>>e.g.
>>
>> >>> int = 42
>> >>> int
>>42
>> >>> __builtins__.int
>><class 'int'>
>> >>>
>>
>
>You mean built-in objects never go away, even when they are no longer 
>referenced?

Well, the builtins module itself has a reference. But what greg's 
showing you above it the "int" class/type. You've got an in in play in 
the code above - the class will of course exist. But the builtin classes 
(and other names) always exist because they're built in.

Cheers,
Cameron Simpson <cs at cskk.id.au>