GCD in standard library?

[Steven Taschuk]

Quoth Blake Garretson:
> [...] I'm just guessing it is very common
> for people to have to add this to their programs:
> 
> def gcd(x,y):
>   if x % y == 0: return y
>   else: return gcd(y,x%y)

I for one haven't needed this in Python yet, but if I did I'd do
it this way:
	def gcd(a, b):
		while b:
			a, b = b, a % b
		return abs(a)
which (1) avoids the unnecessary recursion, (2) gives the right
answer for zero operands, and (3) gives a predictable and
defensible, if not obviously right, answer for negative operands.

I don't know why it's not in the standard library as you inquire;
one reason may be simply that it's not in the standard C math
library.

-- 
Steven Taschuk                               staschuk at telusplanet.net
"What I find most baffling about that song is that it was not a hit."
                            -- Tony Dylan Davis (CKUA)