Python - Remove Duplicate Items From a Sequence

Submitted by Corey Goldberg on Thu, 29/03/2007 - 18:30.

Say you have a sequence like:

[1, 1, 2, 2, 2, 3, 4, 4, 4]

... and you want a sequence containing all the unique items (remove duplicates) like:

[1, 2, 3, 4]

Here is a function to do it:

def remove_dups(seq):
    x = {}
    for y in seq:
        x[y] = 1
    u = x.keys()
    return u

or a one-liner:

u = [x for x in seq if x not in locals()['_[1]']]

update: in the comments below, some other ways were suggested..

with 'set'.. like this:

u = list(set(seq))

or with a dictionary.. like this:

u = dict.fromkeys(seq).keys()

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