I am facing a problem where I am really confused about it.
I am trying to compare to instances using:
if inst1 == inst2
These instances have a overridden method __str__ which returns same
string. The condition result is true although they are different
instances.
If I use:
if id(inst1) == id(inst2)
The results is false. What's happening here?
If I am trying to store this pair in a set where other instances are
already stored, but it's not storing it. Although I am sure that there
is no pair already stored of same but even if Set is comparing by
using string return by __str__ method then it won't.
How do I solve this?
Is this mean when you have overridden __str__ method then it comapre
with results of __str__ or else it will comapre whether they are the
same instances?
7  1693 
On Jul 24, 6:50*pm, King <animator...@gm ail.comwrote:
I am facing a problem where I am really confused about it.
I am trying to compare to instances using:
if inst1 == inst2
These instances have a overridden method __str__ which returns same
string. The condition result is true although they are different
instances.
If I use:
if id(inst1) == id(inst2)
The results is false. What's happening here?
If I am trying to store this pair in a set where other instances are
already stored, but it's not storing it. Although I am sure that there
is no pair already stored of same but even if Set is comparing by
using string return by __str__ method then it won't.
How do I solve this?
Is this mean when you have overridden __str__ method then it comapre
with results of __str__
No. Do you have a __cmp__ method, or an __eq__ method? Any other
__twounderscore s__ methods?
It is impossible to tell what is going on from your description.
Please supply the source of a *short* class that demonstrates the
problem, and demonstrate it.
King wrote:
Is this mean when you have overridden __str__ method then it comapre
with results of __str__ or else it will comapre whether they are the
same instances?
Comparisons uses __cmp__ or the rich comparison set; see http://docs.python.org/ref/customization.html
for details.
Sets and dictionaries, also relies on hashing (the __hash__ method, also
described on the linked page).
The __str__ method only affects printing and conversion to string.
</F>
The only methods I do have in class is __init__ and __str__.
How ever inst1 and inst2 is coming from a dictionary where I stored
them with a unique id.
inst1 = stored[id]
inst2 = stored[id]
Is this makes a difference? I will rip down the piece of code giving
me problem and post.
King wrote:
The only methods I do have in class is __init__ and __str__.
How ever inst1 and inst2 is coming from a dictionary where I stored
them with a unique id.
inst1 = stored[id]
inst2 = stored[id]
Is this makes a difference?
unlikely (well, if that's the literal code, both variables will point to
the same variable, but I guess that's not what you meant).
I will rip down the piece of code giving me problem and post.
please do. and don't be surprised if you find the problem while doing
so ;-)
</F>
No,
The the class is not subclass of another one. Problem still persist.
The code is pretty huge and I am trying to post the information as
clear as possible.
King skrev:
The the class is not subclass of another one. Problem still persist.
The code is pretty huge and I am trying to post the information as
clear as possible.
feel free to *add* stuff to the following example until it breaks, if
that's easier:
>>class Spam:
.... def __init__(self, label):
.... self.label = label
.... def __str__(self):
.... return self.label
....
>>a = Spam("an object")
a
<__main__.Spa m instance at 0xb7e8faac>
>>print a
an object
>>b = Spam("an object")
b
<__main__.Spa m instance at 0xb7e8fb6c>
>>print b
an object
>>a == b
False
>>a is b
False
>>str(a) == str(b)
True
</F>
On Jul 24, 2008, at 7:53 PM, King wrote:
The the class is not subclass of another one. Problem still persist.
The code is pretty huge and I am trying to post the information as
clear as possible.
Mark V. Shaney, from Dissociated Press, I presume?
--
PA. http://alt.textdrive.com/nanoki/ This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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