subsets.py 文件源码

def ksubsets(superset, k):
    """
    Finds the subsets of size k in lexicographic order.

    This uses the itertools generator.

    Examples
    ========

    >>> from sympy.combinatorics.subsets import ksubsets
    >>> list(ksubsets([1,2,3], 2))
    [(1, 2), (1, 3), (2, 3)]
    >>> list(ksubsets([1,2,3,4,5], 2))
    [(1, 2), (1, 3), (1, 4), (1, 5), (2, 3), (2, 4), \
    (2, 5), (3, 4), (3, 5), (4, 5)]

    See Also
    ========
    class:Subset
    """
    return combinations(superset, k)