Python List Comprehension, With Unique Items

Is there a way to make a list comprehension in Python that only contains unique items? My original idea was to use something like this : new_items = [unicode(item) for item in item

Solution 1:

Well, there is no ordered set, but we can misuse OrderedDict:

from collections importOrderedDictt="never gonna give you up"
OrderedDict.fromkeys(t).keys()

Gives:

['n', 'e', 'v', 'r', ' ', 'g', 'o', 'a', 'i', 'y', 'u', 'p']

Solution 2:

Your original idea works with a set comprehension:

new_items = {unicode(item) for item in items}

Solution 3:

I short one liner might be:

s = "some string"unique_items = [unicode(ch) for ch in sorted(set(s), key=s.index)]

Solution 4:

Make it a helper function, like so.

defunique_iter(iterable):
  seen = set()
  for item in iterable:
    if item in seen:
      continue
    seen.add(item)
    yield item

for ch in unique_iter("never gonna give you up"):
  print ch,

outputs

n e v r g o a i y u p