Question

Possible Duplicate:
Python: removing duplicates from a list of lists

Say i have list

a=[1,2,1,2,1,3]

If all elements in a are hashable (like in that case), this would do the job:

list(set(a))

But, what if

a=[[1,2],[1,2],[1,3]]

?

Answer 1

Python 2

>>> from itertools import groupby
>>> a = [[1,2],[1,2],[1,3]]
>>> [k for k,v in groupby(sorted(a))]
[[1, 2], [1, 3]]

Works also in Python 3 but with caveat that all elements must be orderable types.