The Cost of Dynamism (was Re: Pyhon 2.x or 3.x, which is faster?)

Jussi Piitulainen jussi.piitulainen at helsinki.fi
Thu Mar 24 10:34:13 EDT 2016


BartC writes:
> On 24/03/2016 14:08, Jon Ribbens wrote:
>> On 2016-03-24, BartC wrote:
>>> I'd presumably have to do:
>>>
>>>    for i in range(len(L)):
>>>      L[i]=0
>>
>> That's kind've a weird thing to want to do;
>
> The thing I'm trying to demonstrate is changing an element of a list
> that you are traversing in a loop. Not necessarily set all elements to
> the same value.

You understand correctly, but it may be more natural in practice to
write it this way:

    for k, item in enumerate(them):
        them[k] = f(item)

I _think_ I might write it that way even when "f(item)" does not depend
on the old value at all, but I don't expect to be in that situation.



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