Which way do you prefer?

styles.py

# Partition the following data into 2 lists: males and females
users = [{
          "name": "user_%s" % x,
          "gender": 'f' if x % 3 is random.randint(0,3) else 'm'
          }
         for x in range(1, 100)]
 
# Which way do you prefer?
 
# 1
males, females = [], []
for user in users:
    if user['gender'] is 'm':
        males.append(user)
 
    if user['gender'] is 'f':
        females.append(user)
 
# 2
males = [u for u in users if u['gender'] is 'm']
females = [u for u in users if u['gender'] is 'f']
 
# 3
def reduce_func((males, females), user):
    if user['gender'] is 'f':
        return (males, females + [user])
 
    if user['gender'] is 'm':
        return (males + [user], females)
 
    return (males, females)
 
(males, females) = reduce(reduce_func, users, ([], []))
 
# 4
(males, females) = reduce(
  lambda (ms, fs), u:
    (ms, fs + [u]) if u['gender'] is 'f' else (ms + [u], fs) if u['gender'] is 'm' else (ms, fs),
  users,
  ([], []))