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Create 2 unique but random items in a list

I need to create a list with unique elements

parties = ['Party A', 'Party B']

I tried this

def party_generator(size=1, chars=string.ascii_uppercase):
    parties = []
    for y in range(2):
        party = ''.join(random.choice(chars) for x in range(size))
        parties.append(''.join(['Party ', party]))
    return parties

But I'm afraid that my code might generate duplicates

party_generator()
['Party S', 'Party S']

How to create a list with unique elements?

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1 answer

Use setfor tracking if you have seen the same random string created before:

def party_generator(size=1, chars=string.ascii_uppercase):
    parties = []
    seen = set()
    while len(parties) < 2:
        party = ''.join(random.choice(chars) for x in range(size))
        if party in seen:
            continue
        seen.add(party)
        parties.append('Party {}'.format(party))
    return parties

This will continue to generate random strings until you have 2 unique values.

random.sample() , , . , ( __len__ __getattr__) size , chars:

class CharacterRange(object):
    def __init__(self, chars, size):
        self.chars, self.size = chars, size

    def __len__(self):
        return len(self.chars) ** self.size

    def __getitem__(self, item):
        if item < 0:
            item = len(self) + item
        if not 0 <= item <= len(self):
            raise IndexError('Index out of range')

        result = []
        for i in range(self.size):
            item, index = divmod(item, len(self.chars))
            result.append(self.chars[index])
        return ''.join(result[::-1])

:

>>> uppercase_len1 = CharacterRange(string.uppercase, 1)
>>> len(uppercase_len1)
26
>>> uppercase_len5[0]
'A'
>>> uppercase_len5[-1]
'Z'
>>> uppercase_len1[10]
'K'
>>> uppercase_len1[24]
'Y'
>>> uppercase_len5 = CharacterRange(string.uppercase, 5)
>>> len(uppercase_len5)
11881376
>>> uppercase_len5[0]
'AAAAA'
>>> uppercase_len5[-1]
'ZZZZZ'
>>> uppercase_len5[1024]
'AABNK'
>>> uppercase_len5[1355453]
'CZDCV'

random.sample():

>>> import random
>>> random.sample(uppercase_len5, 5)
['CUSQB', 'UUUWM', 'MKOFI', 'MYROU', 'AHRWA']

N K .

:

def party_generator(size=1, chars=string.ascii_uppercase):
    return ['Party {}'.format(party) for party in random.sample(CharacterRange(chars, size))]

, , 2 .

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