How to get ordered set? [duplicate]

Question

EDIT: Thanks. I assumed sets were ordered since the output is almost in alphabetical order. But yes I want an ordered set.

def create_table(secret):    
    sec = set(secret) 
    alpha = set("abcdefghiklmnopqrstuvwxyz")
    bet = alpha - sec

    newSecret = secret & bet

    print newSecret



 OUTPUT:  set(['A', 'C', 'B', 'E', 'D', 'G', 'F', 'I', 'H', 'K', 'M', 'L', 'O', 'N', 'Q', 'P', 'S', 'R', 'U', 'T', 'W', 'V', 'Y', 'X', 'Z'])

How do I create an ordered set?

Example: If I take the string "mathematics" and the string "abcdefghiklmnopqrstuvwxyz", essentially the new string should be "MATHEICSBDFGKLNOPQRUVWXYZ" (assuming i have the code to uppercase the string). There is no 'J' in this string so it isn't a typo.

I'm trying to take the unique characters from the variable 'secret' and unique characters from the variable 'alpha' and get ordered unique characters from both.

Answer 1

Python doesn't have an OrderedSet; usually we fake it with an OrderedDict.

For example:

>>> from collections import OrderedDict
>>> s = "mathematics"
>>> alpha = "abcdefghiklmnopqrstuvwxyz"
>>> d = OrderedDict.fromkeys(s+alpha)
>>> d
OrderedDict([('m', None), ('a', None), ('t', None), ('h', None), ('e', None), ('i', None), ('c', None), ('s', None), ('b', None), ('d', None), ('f', None), ('g', None), ('k', None), ('l', None), ('n', None), ('o', None), ('p', None), ('q', None), ('r', None), ('u', None), ('v', None), ('w', None), ('x', None), ('y', None), ('z', None)])
>>> ''.join(d)
'matheicsbdfgklnopqruvwxyz'

This doesn't quite work as well as an OrderedSet would, but is often close enough for government work.