Grab unique tuples in python list, irrespective of order

Question

I have a python list:

[ (2,2),(2,3),(1,4),(2,2), etc...]

What I need is some kind of function that reduces it to its unique components... w

Answer 1

If order does not matter

If the order of the result is not critical, you can convert your list to a set (because tuples are hashable) and convert the set back to a list:

>>> l = [(2,2),(2,3),(1,4),(2,2)]
>>> list(set(l))
[(2, 3), (1, 4), (2, 2)]

If order matters

(UPDATE)

As of CPython 3.6 (or any Python 3.7 version) regular dictionaries remember their insertion order, so you can simply issue.

>>> l = [(2,2),(2,3),(1,4),(2,2)]
>>> list(dict.fromkeys(l))
[(2, 2), (2, 3), (1, 4)]

---

(OLD ANSWER)

If the order is important, the canonical way to filter the duplicates is this:

>>> seen = set()
>>> result = []
>>> for item in l:
...     if item not in seen:
...         seen.add(item)
...         result.append(item)
... 
>>> result
[(2, 2), (2, 3), (1, 4)]

Finally, a little slower and a bit more hackish, you can abuse an OrderedDict as an ordered set:

>>> from collections import OrderedDict
>>> OrderedDict.fromkeys(l).keys() # or list(OrderedDict.fromkeys(l)) if using a version where keys() does not return a list
[(2, 2), (2, 3), (1, 4)]