[Tutor] Else vs. Continue

[Alan Gauld]

On 24/11/13 22:38, Alan Gauld wrote:

Responding to my own post, never a good sign :-(

> primes = []
> for n in range(1000)
>     if n%2 == 0: even numbers aren't prime
>        continue
>     else:
>        if isPrime(n):
>           primes.append(n)
>
> Now the continue means the isPrime test never gets executed,
> saving a lot of processing. Without continue you would need
> to execute the test and the only way to save the time would
> be to move the n%2 test inside the isPrime() function

As soon as I posted it I realized that wasn't true, you could
do this instead...

for n in range(1000):
    if n%2 == 1:
      if isPrime(n):
         primes.append(n)

So a bad example, sorry.
DeMorgan wins again.

-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.flickr.com/photos/alangauldphotos