On Wed, May 20, 2015 at 1:51 PM, Mario Figueiredo <mar...@gmail.com> wrote:
> On Wed, 20 May 2015 03:07:03 +1000, Steven D'Aprano
> <steve+comp.lang.pyt...@pearwood.info> wrote:
>
>>Yes, a slice can be expensive, if you have (say) a ten billion element list,
>>and take a slice list[1:].
>
> Since nothing seems to surprise you and you seem so adamant on calling
> anyone being surprised by it, maybe I will surprise you if you
> actually run the code I posted on the OP and witness for yourself that
> even on a 50 element list will take 3 seconds to execute on an intel
> i5.
I suspect you've made a mistake in your timing. I measure it at 20.8
microseconds on a Xeon W3690.
>>> def minimum(values):
... if len(values) == 1:
... return values[0]
... else:
... m = minimum(values[1:])
... return m if m < values[0] else values[0]
...
>>> from timeit import Timer
>>> t = Timer("minimum(values)", setup="from __main__ import minimum; values =
>>> list(range(50))")
>>> min(t.repeat(number=100000))
2.077940827002749
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