Specifies an empty collection that you can use instead of creating a new one with no items 指定一个可以使用的空集合，而不是创建一个不带任何项的新集合。
It then displays the names in the collection , and finally empties the collection without disposing of the 示例接着显示集合中的名称，最后清空集合但不释放
If this configuration inherits all of its settings , or no locations are defined , an empty collection is returned 如果此配置继承了它的全部设置，或未定义位置，则返回一个空集合。
For example , iteratively or recursively nulling elements of a collection where the collection object would otherwise be eligible for garbage collection actually adds overhead to a program rather than helping the garbage collector 例如，迭代地或者递归地赋空集合内的元素使得这些集合中的对象能够满足垃圾收集的条件，实际上是增加了系统的开销而不是帮助垃圾收集。
The representation theories of mp - filter which is created by an non - empty set of a implication algebra on a partial ordered set with condition ( c ) are obtained at first . and it ' s proved that the set which contains all mp - filters of a implication algebra x , denoted by mf ( x ) = { f x f is a filter of x } , is a distributive lattice and a complete lattice also in the view of the concept of mp - filter . then the fuzzy filter of a implication algebra is discussed , and the relations between mp - filter and fuzzy filter are obtained 借助于mp -滤子的概念，得到了偏序集上具有条件( c )的蕴涵代数中由非空集合所生成mp滤子的表示定理，证明了由其上所有mp -滤子组成的集合mf ( x )是一个完备的分配格；得到了蕴涵代数中fuzzy滤子与mp滤子的关系，给出了fuzzy滤子成为fuzzy素滤子的若干刻画；并利用mp -滤子和fuzzy滤子，刻画了一类偏序集上蕴涵代数的结构。
