From http://www.peterbe.com/plog/uniqifiers-benchmark Various functions to uniqify a list in python. Some preserve the orders other don't.

uniqify_list.py

def f1(seq):
   # not order preserving
   set = {}
   map(set.__setitem__, seq, [])
   return set.keys()

def f2(seq): 
   # order preserving
   checked = []
   for e in seq:
       if e not in checked:
           checked.append(e)
   return checked

def f3(seq):
   # Not order preserving
   keys = {}
   for e in seq:
       keys[e] = 1
   return keys.keys()

def f4(seq): 
   # order preserving
   noDupes = []
   [noDupes.append(i) for i in seq if not noDupes.count(i)]
   return noDupes

def f5(seq, idfun=None): 
   # order preserving
   if idfun is None:
       def idfun(x): return x
   seen = {}
   result = []
   for item in seq:
       marker = idfun(item)
       # in old Python versions:
       # if seen.has_key(marker)
       # but in new ones:
       if marker in seen: continue
       seen[marker] = 1
       result.append(item)
   return result

def f6(seq):
   # Not order preserving    
   set = Set(seq)
   return list(set)