Creating Linked Lists in Python

grocery_stocker cdalten at gmail.com
Sat Mar 21 18:34:21 CET 2009


On Mar 21, 10:03 am, Tim Chase <python.l... at tim.thechases.com> wrote:
> >>>    transitions = {
> >>>      # values are tuples of (newstate, transition_function)
> >>>      STATE_A: [
> >>>        (STATE_B, lambda x: x > 5),
> >>>        (STATE_C, lambda x: x > 10),
> >>>        (STATE_D, lambda x: x > 100),
> >>>        ],
> >>>      STATE_B: [
> >>>        (STATE_A, lambda x: x < 5),
> >>>        (STATE_C, lambda x: x > 10),
> >>>        ],
> >>>      STATE_C: [
> >>>        (STATE_B, lambda x: x < 10),
> >>>        (STATE_D, lambda x: x > 100),
> >>>        ],
> >>>      STATE_D: [],
> >>>      }
>
> >> And if you don't mind me asking. How do you invoke lambda from
> >> transitions?
>
> > Disregard that. I think I figured it out.
>
> > If you had something like...
>
> >>>> transitions = {1: [2, lambda x: 2*x]}
>
> > You would probably call it like...
>
> >>>> transitions[1][1](4)
> > 8
>
> I tend to use them with tuple assignment which I find reads more
> cleanly than directly indexing:
>
>    for input in source():
>      available_states = []
>      for new_state, function in transitions[state]:
>        if function(input):
>          available_states.append(new_state)
>      do_something(available_states)
>


To my defense, I would like to say that I started with python like 2
weeks ago.




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