9 examples of 'python combinations of two lists' in Python

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def combinations(a, b):
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    """ Returns all combinations of
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     - fast.forwards->fast.backwards
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     - fast.forwards->slow.backwards
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     - slow.forwards->fast.backwards
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     - slow.forwards->slow.backwards
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    """
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    return list(itertools.chain.from_iterable(
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        [
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            list(itertools.product(*zip(*item)))
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            for item in correspondences(a, b)
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        ]
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    ))

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def all_combinations(items):
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    variants = []
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    for n in range(len(items)+1):
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        variants.extend(itertools.combinations(items, n))
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    return variants

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def combinations(c, r):
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    # combinations('ABCD', 2) --> AB AC AD BC BD CD
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    # combinations(range(4), 3) --> 012 013 023 123
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    pool = tuple(range(c))
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    n = len(pool)
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    if r > n:
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        return
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    indices = list(range(r))
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    yield tuple(pool[i] for i in indices)
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    while True:
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        for i in reversed(list(range(r))):
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            if indices[i] != i + n - r:
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                break
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        else:
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            return
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        indices[i] += 1
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        for j in range(i+1, r):
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            indices[j] = indices[j-1] + 1
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        yield tuple(pool[i] for i in indices)

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def testCombinations(self):
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    for i in range(15):
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        case = range(i)
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        k = random.randrange(len(case) + 1)
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        result = combinations(case, k)
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        result = set(map(tuple, result))
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        expect = itertools.combinations(case, k)
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        expect = set(expect)
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        self.assertEqual(result, expect)

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def combine1(self, n, k):
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    """
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    :param n:
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    :param k:
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    :return:
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    Recursive
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    """
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    if k == 0:
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        return [[]]
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    return [pre + [i] for i in range(1, n + 1) for pre in self.combine(i - 1, k - 1)]

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def get_combinations(to_combine):
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    combination_found = True
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    while combination_found:
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        combination_found = False
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        combos = itertools.combinations(to_combine,2)
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        removed = []
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        for d in combos:
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            if sum([(d[0] == r) or (d[1] == r) for r in removed]):
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                continue
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            if d[0].issuperset(d[1]):
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                [to_combine.remove(x) for x in to_combine if x == d[1]]
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                removed.append(d[1])
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            elif d[1].issuperset(d[0]):
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                [to_combine.remove(x) for x in to_combine if x == d[0]]
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                removed.append(d[0])
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            elif len(d[0].intersection(d[1])) > 0:
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                combination_found = True
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                to_combine.append(set.union(d[0],d[1]))
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                [to_combine.remove(x) for x in to_combine if x == d[0]]
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                [to_combine.remove(x) for x in to_combine if x == d[1]]
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                removed.append(d[0])
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                removed.append(d[1])
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    return to_combine

13
def get_combinations(yag):
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    """ Creates permutations of possible inputs """
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    tos = (None, (yag.user), [yag.user, yag.user],
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           {yag.user: 'me', yag.user + '1': 'me'})
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    subjects = ('subj', ['subj'], ['subj', 'subj1'])
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    contents = (None, ['body'], ['body', 'body1', '<h2>Text</h2>'])
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    results = []
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    for row in itertools.product(tos, subjects, contents):
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        options = {y: z for y, z in zip(['to', 'subject', 'contents'], row)}
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        options['preview_only'] = True
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        results.append(options)
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    return results

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def xuniqueCombinations(items, n):
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    if n == 0:
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        yield []
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    else:
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        for i in xrange(len(items)):
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            for cc in xuniqueCombinations(items[i + 1:], n - 1):
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                yield [items[i]] + cc

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def xuniqueCombinations(items, n):
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    if n==0: yield []
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    else:
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        for i in xrange(len(items)):
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            for cc in xuniqueCombinations(items[i+1:],n-1):
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                yield [items[i]]+cc