Closest Pair of Points in Python

from math import sqrt, pow

def distance(a, b):
  return sqrt(pow(a[0] - b[0],2) + pow(a[1] - b[1],2))

def bruteMin(points, current=float("inf")):
  if len(points) < 2: return current
  else:
    head = points[0]
    del points[0]
    newMin = min([distance(head, x) for x in points])
    newCurrent = min([newMin, current])
    return bruteMin(points, newCurrent)

def divideMin(points):
  half = len(sorted(points))/2
  minimum = min([bruteMin(points[:half]), bruteMin(points[half:])])
  nearLine = filter(lambda x: x[0] > half - minimum and x[0] < half + minimum, points)
  return min([bruteMin(nearLine), minimum])

list1 = [(12,30), (40, 50), (5, 1), (12, 10), (3,4)]
print divideMin(list1)

hello,
I am searching for an algorithm like this and luckily found this working snippet.
After some unit test, I've found an issue.
You can duplicate the issue with replacing line 21 by
list1 = [(1, 496.5), (12,30), (40, 50), (5, 1), (12, 10), (3,4), (1, 496), (1, 497)] #bug
The correct output would be 0.5 but 1 was returned.
This algorithm needs points sorted allowing you split them into halves in line 17.
I fixed this by simply adding
points = sorted(points)
at the top of divideMin.
Hope this helps, it an old thread though.
: D