The new additions to SPL add some useful functionality to PHP that is easy to use, as well as implementations of data structures, such as doubly linked lists, stacks, heaps, and queues.
SPL中的新补充？ php添加了一些有用的并且易于使用的功能，以及数据结构的实现，例如双重链接列表、栈、堆和队列。
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