[Tutor] Passing perimeters in dictionary values?

[nathan virgil]

I'm not familiar with lambdas yet, and I don't think this book will
introduce me to them; they aren't listed in the index, anyway.

Adding a bunch of single-line functions would work, but I'm not sure how
much better that is then the if structure. I think it's what I'm going to go
with, anyway. At least until I can learn about lambdas, or even some other
solution.

On Tue, Feb 24, 2009 at 2:42 PM, Kent Johnson <kent37 at tds.net> wrote:

> On Tue, Feb 24, 2009 at 2:03 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 can define a function that does what you want:
> def eat2():
>  crit.eat(2)
>
> Then put eat2 in your dictionary:
> choices = { '2': eat2, ...}
>
> Alternately you can use lambda expressions to do the same thing
> without an explicit def:
> choices = { '2': lambda: crit.eat(2), ... }
>
> Kent
>
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