1.方法一：
>>> a=[1,1,2,2,3,3]
>>> b=[]
>>> for i in a:
... if i not in b:
... b.append(i)
...
>>> b
[1, 2, 3]
>>>
2.方法二：
>>> a=[1,1,2,2,3,3]
>>> for i in a:
... for j in range(a.count(i)-1):
... a.remove(i)
...
>>> a
[1, 2, 3]
>>>
3.方法三：
a=[1,1,2,2,3,3]
for i in a:
while a.count(i)>1:
a.remove(i)
print a
4.方法四：
>>> a=[1,1,2,2,3,3]
>>> list(set(a))
[1, 2, 3]
>>>
5.方法五：
>>> list({}.fromkeys([1,1,1,2,2,3,3]))
[1, 2, 3]