[Tutor] List comprehension question

[Alan Gauld]

"Stefan Behnel" <stefan_ml at behnel.de> wrote

>> Why use math.sqrt() instead of just using the ** operator?
>>
>> return sum(x for x in range(1, int(n**0.5)) if n%x == 0)
>>
> Since this operation is only evaluated once in the whole runtime of 
> the loop, I think readability beats the likely very tiny performance 
> difference here.

Ah, I wondered if readability was the reason. I hadn't thought about
it hard enough to notice the sqrt() would only be called once! :-)

As to readability I personally prefer the exponentiation sign (or even 
pow()!)
and don't think I have ever used math.sqrt() in my 12 years of Python.
But I recognise that some may prefer sqrt, especially if they don't
have a math background.

Alan G.