Why is my code faster with append() in a loop than with a large list?

[Dave Angel]

MRAB wrote:
> <div class="moz-text-flowed" style="font-family: -moz-fixed">Dave 
> Angel wrote:
> [snip]
>> It would probably save some time to not bother storing the zeroes in 
>> the list at all.  And it should help if you were to step through a 
>> list of primes, rather than trying every possible int.  Or at least 
>> constrain yourself to odd numbers (after the initial case of 2).
>>
> Or stop looking for more factors when you've passed the square root of
> num. I don't know what effect there'll be on the time if you recalculate
> the square root when num changes (expensive calculation vs smaller
> search space).
>
> </div>
>
But if I remember the code, it stopped when the quotient is one, which 
is usually sooner than the square root.  And no need to precalculate the 
square root.