s...@uce.gov wrote:
How can I do something like this in python:
#!/usr/bin/python3.1
class MyNumbers:
def __init__(self, n):
self.original_value = n
if n <= 100:
self = SmallNumers(self)
else:
self = BigNumbers(self)
class SmallNumbers:
def __init__(self, n):
self.size = 'small'
class BigNumbers:
def __init__(self, n):
self.size = 'big'
t = MyNumbers(200)
When I do type(t) it says MyNumbers, while I'd want it to be
BigNumbers, because BigNumbers and SmallNumbers will have different
methods etc...
Do I need to use metaclasses?
Thanks.
You simply don't return inconsistent types with a return statement. This
is a general rule in programming that has probably exceptions but
regarding what you're saying, you clearly don't want to do that.
Immagine the following code:
oNumber = MyNumbers(random.int(100)) # note that oNumber is not a
MyNumbers instance... quite confusing don't you think ?
oNumber. ... wait a minute, which methods am I allowed to call ???
SmallNumbers adn BigNumbers have differents methods.
Some rules to follow, until you get some experience with python:
* use consistent types for method parameters.
* use consistent types for returned values.
* a class constructor should return an instance of that very same class.
JM
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