A certainl part of an if() structure never gets executed.

[Michael Weylandt]

On Jun 17, 2013, at 6:17, Νίκος <support at superhost.gr> wrote:

> On 16/6/2013 9:53 μμ, R. Michael Weylandt wrote:
>> On Sun, Jun 16, 2013 at 2:47 PM, Ferrous Cranus <support at superhost.gr> wrote:
>>> On 16/6/2013 2:13 μμ, Jussi Piitulainen wrote:
>>>> 
>>>> If, instead of the above, you have
>>>> 
>>>> a = 6
>>>> b = a
>>>> b = 5
>>>> 
>>>> you will find that b == 5 and a == 6. So b is not the same as a. Else
>>>> one would have changed when the other changed. I would say that a and
>>>> b are different variables. They had the same value, briefly.
>>> 
>>> 
>>> If they were different variables then they would have different memory
>>> addresses and they would act like two different objects.
>>> 
>>> But... both a and b are for a fact mappings for the same memory address as
>>> seen form the following command.
>>> 
>>>>>> id(a) == id(b)
>>> True
>>> 
>>> They are like the same object with 2 different names.
>> 
>> This will depend on when the test is run:
>> 
>> a = 6
>> b = a
>> a is b # True
>> 
>> b = 5
>> a is b # False
>> 
>> The latter is false because the binding of "b" to the int 6 was broken
>> in order to bind b to the int 5.
> 
> Very surprising.
> a and b was *references* to the same memory address, it was like a memory address having 2 names to be addresses as.
> 
> b = a name we use to address some memory location, do we agree on that?
> 
> So, b = 6, must have changed the stored value of its mapped memory location, but given you example it seems its changing the mapping of b to some other memory address.
> 
> I don't follow its act of course.

I'm having trouble understanding your grammar in the above, but please re-read my note on the dual behavior of `=` here:

http://mail.python.org/pipermail/python-list/2013-June/649990.html

Michael
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