方法一:回归实现
def powersetsrecursive(items): """use recursive call to return all subsets of items, include empty set""" if len(items) == 0: #if the lsit is empty, return the empty list return [[]] subsets = [] first_elt = items[0] #first element rest_list = items[1:] #strategy:get all subsets of rest_list; for each of those subsets, a full subset list #will contain both the original subset as well as a version of the sebset that contains the first_elt for partial_sebset in powersetsrecursive(rest_list): subsets.append(partial_sebset) next_subset = partial_sebset[:] +[first_elt] subsets.append(next_subset) return subsets
def powersetsrecursive2(items): # the power set of the empty set has one element, the empty set result = [[]] for x in items: result.extend([subset + [x] for subset in result]) return result
方法二:二进制法
def powersetsbinary(items): #generate all combination of n items n = len(items) #enumerate the 2**n possible combinations for i in range(2**n): combo = [] for j in range(n): #test jth bit of integer i if(i >> j ) % 2 == 1: combo.append(items[j]) yield combo
相关推荐:
python判断一个集合是否为另一个集合的子集方法
python实现简单文本字符串处理的方法
以上就是python实现求一个集合所有子集的示例的详细内容。
