Question

Given multiple (x,y) ordered pairs, I want to compare distances between each one of them. So pretend I have a list of ordered pairs:

pairs = [a,b,c,d,e,f] 

I have a function that takes two ordered pairs and find the distance between them:

def distance(a,b):     from math import sqrt as sqrt     from math import pow as pow     d1 = pow((a[0] - b[0]),2)     d2 = pow((a[1] - b[1]),2)     distance = sqrt(d1 + d2)     return distance 

How can I use this function to compare every ordered pair to every other ordered pair, ultimately finding the two ordered-pairs with the greatest distance between them?

Psuedopsuedocode:

     distance(a,b)      distance(a,c)      ...      distance(e,f) 

Any help would be tremendously appreciated.

Answer 1

try:      from itertools import combinations  except ImportError:      def combinations(l, n):         if n != 2: raise Exception('This placeholder only good for n=2')         for i in range(len(l)):             for j in range(i+1, len(l)):                 yield l[i], l[j]   coords_list = [(0,0), (3,4), (6,8)]  def distance(p1, p2):     return ( ( p2[0]-p1[0] ) ** 2 + ( p2[1]-p1[1] )**2 ) ** 0.5  largest_distance, (p1, p2) = max([      (distance(p1,p2), (p1, p2)) for (p1,p2) in combinations(coords_list, 2)      ])   print largest_distance, p1, p2