Gerardo Herzig wrote:
> Hi all. Im in this situation: I want to perform several kind of
> (validating) methods to a given value.
> Lets say i have a class named Number, and the following methods:
> is_really_a_number(),
> is_even(),
> is_greater_than_zero(),
> and so on. All of them returning booleans.
>
> I want the collect_validators() method is to execute any of the above
> methods, and collect their names as items of a list (wich will be the
> collect_validators() return value).
>
> My first approach is:
>
> [code]
> def collect_validators(self):
> v_dict = { 'is_really_a_number': is_really_a_number,
> 'is_even': is_even,
> 'is_greater_than_zero', is_greater_than_zero
> }
>
> for name, meth in v_dict.items():
> result = meth()
> if result: yield name
> [/code]
>
> I wondering if is this a good pattern to apply, i like the way it looks
> like, at least to me it looks `natural', but...im calling every method
> twice here? One in v_dict and again on the dict iteration?
>
> Any suggestion will be great!
>
> Thanks!
> Gerardo
You are not calling every method twice. You are painstakingly typing out
their names twice. But fortunately, functions and methods have a
__name__ attribute which makes a this typing redundant. I would give
your class instances a _validators attribute which is a list of
validating methods, then make the generator like this:
def collect_validators(self):
for v in self._validators:
if v():
yield v.__name__
James
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