我想为一个名为Multiset的类创建不同的方法。
我有所有必需的方法,但我不确定如何编写交集、并集和子集方法。
对于交集和并集,我的代码是这样开始的:
def intersect(var)
x = Multiset.new
end
下面是一个示例:
X = [1, 1, 2, 4]
Y = [1, 2, 2, 2]
那么X
和Y
的交集就是[1, 2]
。
发布于 2011-04-15 22:28:50
利用可以通过&
(交集)、-
(差集)和|
(并集)对数组进行集合操作这一事实。
很明显,我没有实现规范的MultiSet,但这应该可以让您开始:
class MultiSet
attr_accessor :set
def initialize(set)
@set = set
end
# intersection
def &(other)
@set & other.set
end
# difference
def -(other)
@set - other.set
end
# union
def |(other)
@set | other.set
end
end
x = MultiSet.new([1,1,2,2,3,4,5,6])
y = MultiSet.new([1,3,5,6])
p x - y # [2,2,4]
p x & y # [1,3,5,6]
p x | y # [1,2,3,4,5,6]
发布于 2011-04-15 22:21:57
我假设X
和Y
是数组?如果是这样的话,有一种非常简单的方法:
x = [1, 1, 2, 4]
y = [1, 2, 2, 2]
# intersection
x & y # => [1, 2]
# union
x | y # => [1, 2, 4]
# difference
x - y # => [4]
发布于 2018-12-26 20:46:46
如果Multiset
从Array
类扩展而来
x = [1, 1, 2, 4, 7]
y = [1, 2, 2, 2]
z = [1, 1, 3, 7]
友联市
x.union(y) # => [1, 2, 4, 7] (ONLY IN RUBY 2.6)
x.union(y, z) # => [1, 2, 4, 7, 3] (ONLY IN RUBY 2.6)
x | y # => [1, 2, 4, 7]
差异
x.difference(y) # => [4, 7] (ONLY IN RUBY 2.6)
x.difference(y, z) # => [4] (ONLY IN RUBY 2.6)
x - y # => [4, 7]
交叉点
x.intersection(y) # => [1, 2] (ONLY IN RUBY 2.7)
x & y # => [1, 2]
有关Ruby2.6中新方法的更多信息,可以查看this blog post about its new features
https://stackoverflow.com/questions/5678108
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