python 去掉list中的重复元素

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)