apyori.py 文件源码

def gen_ordered_statistics(transaction_manager, record):
    """
    Returns a generator of ordered statistics as OrderedStatistic instances.

    Arguments:
        transaction_manager -- Transactions as a TransactionManager instance.
        record -- A support record as a SupportRecord instance.
    """
    items = record.items
    for combination_set in combinations(sorted(items), len(items) - 1):
        items_base = frozenset(combination_set)
        items_add = frozenset(items.difference(items_base))
        confidence = (
            record.support / transaction_manager.calc_support(items_base))
        lift = confidence / transaction_manager.calc_support(items_add)
        yield OrderedStatistic(
            frozenset(items_base), frozenset(items_add), confidence, lift)