Python列表去掉重复元素的一种方法：
>>> L = [1, 2, 3, 4, 1, 2, 3, 4, 5]
>>> [x for x in L if x not in locals()['_[1]']]
[1, 2, 3, 4, 5]
解释如下：
down vote Referencing a list comprehension as it is being built...
You can reference a list comprehension as it is being built by the symbol '_[1]'. For example, the following function unique-ifies a list of elements without changing their order by referencing its list comprehension.
def unique(my_list):
return [x for x in my_list if x not in locals()['_[1]']]