[Tutor] Passing perimeters in dictionary values?

[Andre Engels]

On Wed, Feb 25, 2009 at 12:47 AM, Andre Engels <andreengels at gmail.com> wrote:
> - Show quoted text -
> On Tue, Feb 24, 2009 at 8:03 PM, nathan virgil <sdragon1984 at gmail.com> wrote:
>> I'm experimenting with OOP using the Critter Caretaker script from Python
>> Programming for the Absolute Beginner as my basis. I've noticed that a
>> dictionary/function combo is a great way to handle menus, and so I've
>> adapted the menu to read as:
>>
>>
>> selection = raw_input("Choice: ")
>> choices = {"0":quit, "1":crit.talk, "2":crit.eat, "3":crit.play}
>> choice = choices[selection]
>> choice()
>>
>> so that I can call methods from a dictionary, instead of having an
>> excruciatingly long if structure. Unfortunately, the problem I'm running
>> into with this is that I can't pass any perimeters through the dictionary. I
>> can't figure out how, for example, I could have an option that calls
>> crit.eat(2) and another that calls crit.eat(4). The only thing I can think
>> of is going back to the if structure, but my instinct tells me that this is
>> a Bad Idea. What can I do?
>
> You could use a tuple, consisting of the function and its parameter:
>
> choices = {"0": (quit,), "1": (eat,2), "2": (eat,4)}
> choice = choices[selection]
> choice[0](*choice[1:])
>
> But as said by someone else, if the choices are the lowest n natural
> numbers, a list feels more natural:
>
> choices = [(quit,), (eat,2), (eat,4)]
> choices = choice[int(selection)]
> choice[0](*choice[1:])

That last one should of course be:

choices = [(quit,), (eat,2), (eat,4)]
choice = choices[int(selection)]
choice[0](*choice[1:])






-- 
André Engels, andreengels at gmail.com