(Very Newbie) Problems defining a variable

[John Machin]

On Dec 13, 5:18 am, Kirk Strauser <k... at daycos.com> wrote:
> At 2008-12-12T18:12:39Z, "Tim Rowe" <digi... at gmail.com> writes:
>
>
>
> > Is there a tidy way of making rates and thresholds local to get_rate,
> > without recalculating each time? I suppose going object oriented is
> > the proper way.
>
> > #Py3k,UTF-8
>
> > rates = {0: 0.006, 10000: 0.0085, 25000: 0.0124, 50000: 0.0149, 100000: 0.0173}
> > thresholds = list(rates.keys())
> > thresholds.sort()
> > thresholds.reverse()
>
> > def get_rate(balance):
> >     for threshold in thresholds:
> >         if balance >= threshold:
> >             return rates[threshold]
> >     else:
> >         return 0.0
>
> How 'bout:
>
> def get_rate(balance):
>     for threshold, rate in ((100000, .0173),
>                             (50000, .0149),
>                             (25000, .0124),
>                             (10000, .0085),
>                             (0, .006)):
>         if balance > threshold:
>             return rate
>     return .0

(1) you meant "if balance > threshold:"
(2) sequential search can be very fast if the sequence is in
descending order of probability of occurence ... you might like to
consider reversing the order
(3) for a much longer table, binary search using a function from the
bisect module could be considered
(4) in practice, the "default" action would not be "return 0.0";
perhaps something along these lines:

if balance < -overdraft_limit:
   raise Exception(...)
return HUGE