[Edu-sig] Kirby Urner's Sieve of Eratosthenes

Dustin James Mitchell djmitche@midway.uchicago.edu
Thu, 8 Jun 2000 14:33:06 -0500 (CDT)

On Mon, 5 Jun 2000, Kirby Urner wrote:

> PS:  Dustin, would your agree that reduce(mul,terms) and 
> reduce(add,terms) are a useful way to introduce sums and
> products, corresponding to geeky greek symbols capital
> SIGMA and capital PI.  In other words:
> from operator import mul,add
> def sum(terms):
>    """Same as SIGMA (terms is a list)"""
>    return reduce(add,terms)
> def product(terms):
>    """Same as PI (terms is a list)"""
>    return reduce(mul,terms)
> Would these be useful as "math through programming" 
> Python definitions?   
> Note: n! would be the same as product( range(1,n+1) ).

I like this, and it's extremely compact, but I would start by simply using
sum() and product() as black-box operators, and only delving into their
implementation a little bit later (but still before using filters).


|                         Dustin Mitchell                )O(        |