That's just a caching issue. Cpython caches small numbers so that a and b
can be the same object. This works because whenever you change the number
you are reassigning the value as opposed to changing a value within the
object.
a = 10
b = 10
a is b # True
a = 100
a is b # False
print(a, b) # 100, 10
There's no way the python interpreter can get confused so, I guess, the
python programmers though they'd save a little memory that way.
On Mon, Jun 23, 2014 at 3:39 AM, diliup gabadamudalige <dili...@gmail.com>
wrote:
> when you say a=100 and b=100 it is understood that a and b are both given
> TWO values and that both are the same is a coincidence.
> BUT if that is the case how can a is b be TRUE for small integers and a is
> b False for large integers? What logic is Python using here?
>
>
> On Mon, Jun 23, 2014 at 1:07 PM, diliup gabadamudalige <dili...@gmail.com>
> wrote:
>
>> ok
>> look at this!
>> a = 100
>> b = 100
>> a == b
>> True
>> a is b
>> True
>> a = 1000
>> b = 1000
>> a is b
>> False
>> a == b
>> True
>>
>> what on earth is this? what is this logic?
>>
>>
>> On Mon, Jun 23, 2014 at 1:03 PM, Sam Bull <sam.hack...@sent.com> wrote:
>>
>>> On lun, 2014-06-23 at 11:45 +0530, diliup gabadamudalige wrote:
>>> > I called event.clear() cause it says in the Pygame documentation that
>>> > if you leave unused events on the buffer that eventually it may fill
>>> > up and cause the program to crash.
>>>
>>> Yes, but if you are getting everything from the buffer using event.get()
>>> or whatever every frame, then it's not going to fill up, as these
>>> returned events are removed from the queue. As long as you are reading
>>> the whole buffer, say every 100ms, you're going to be fine. Otherwise,
>>> you're just throwing away the events that have arrived between the
>>> event.get() and event.clear() calls.
>>>
>>> >
>>> > if x is True:
>>> > is not correct
>>> >
>>> > if x == True
>>> > is correct?
>>>
>>> This obviously depends on what x is.
>>>
>>> So, if we write:
>>> "foo" is True
>>>
>>> We can clearly see these are not the same object. One is a string, and
>>> the other is the True object. But, if we do:
>>> "foo" == True
>>>
>>> Then, we are asking if the string evaluates to a True value, when
>>> treated as a boolean. And any non-empty string will be considered True,
>>> and so it is equal to True (but not the same object).
>>>
>>>
>>> Futhermore, what Greg was saying is that some objects can be of the same
>>> value and still not be the same object. Thus:
>>> a = 4040
>>> b = 4040
>>> a == b # True
>>> a is b # Could be False
>>>
>>> b = a # b now references the a object itself
>>> a is b # Always True
>>>
>>> This becomes more obvious if we were to use mutable types:
>>> a = [2]
>>> b = [2]
>>> # Obviously, these are two distinct objects
>>> a == b # True
>>> a is b # False
>>> # Changing one, would not change the other, as they are
>>> different
>>> # objects.
>>> a.append(3)
>>> a == b # False
>>>
>>>
>>> On an interesting sidenote, it is not even required that an object is
>>> equal to itself:
>>> a = float("NaN")
>>> a == a # False
>>>
>>
>>
>>
>> --
>> Diliup Gabadamudalige
>>
>> http://www.diliupg.com
>> http://soft.diliupg.com/
>>
>>
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>
>
> --
> Diliup Gabadamudalige
>
> http://www.diliupg.com
> http://soft.diliupg.com/
>
>
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> not the intended recipient or have received it in error, please delete it
> and all copies from your system and notify the sender immediately by return
> e-mail. Any unauthorized reading, reproducing, printing or further
> dissemination of this e-mail or its contents is strictly prohibited and may
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--
Jeffrey Kleykamp
