# Counting distinct lists in a list

I'm trying to remove the duplicate from the list and count the list after removing the duplicates

seq = [[1,2,3], [1,2,3], [2,3,4], [4,5,6]]
new_seq = [[1,2,3], [2,3,4], [4,5,6]]
count = 3


My code takes around 23 seconds for around 66,000 lists in a list

How can I make my code faster?

def unique(seq):
new_seq = []
count = 0
for i in seq:
if i not in new_seq:
new_seq.append(i)
count += 1
return count

• What are you really trying to accomplish? Is this function part of a larger program? Tell us about the context. – 200_success May 6 '16 at 19:41
• The lists comes from another function which calculates an algorithm – jack May 6 '16 at 19:45

Your function is slow because it is O(n2): each element being added to new_seq has to be compared against every previously added element.
Then, to obtain the size of the set, use len().
def unique(seq):