PHP数据的DS扩展

时间:2017-07-17 15:10:15 来源:互联网 作者: 神秘的大神 字体:

   PHP7以上才能安装和使用该数据结构扩展,安装比较简单:

1. 运行命令 pecl install ds

2. 在php.ini中添加 extension=ds.so

3. 重启PHP或重载配置
  • Collection Interface:包含本库中所有数据结构通用功能的基本interface。 It guarantees that all structures are traversable, countable, and can be converted to json using json_encode().

    Ds\Collection implements Traversable , Countable , JsonSerializable {/* 方法 */abstract public void clear ( void )abstract public Ds\Collection copy ( void )abstract public bool isEmpty ( void )abstract public array toArray ( void )
    }

  • Hashable Interfacewhich allows objects to be used as keys.

    Ds\Hashable {/* 方法 */abstract public bool equals ( object $obj )abstract public mixed hash ( void )
    }

  • Sequence InterfaceA Sequence 相当于一个一维的数字key数组, with the exception of a few characteristics:

    Use cases:

    • Wherever you would use an array as a list (not concerned with keys).

    • A more efficient alternative to SplDoublyLinkedList and SplFixedArray.

    • Values will always be indexed as [0, 1, 2, …, size - 1].

    • Only allowed to access values by index in the range [0, size - 1].

    • Vector Class:Vector是自动增长和收缩的连续缓冲区中的一系列值。它是最有效的顺序结构,值的索引直接映射到缓冲区中索引,增长因子不绑定到特定的倍数或指数。其具有以下优缺点:

      Ds\Vector::allocate — Allocates enough memory  a required capacity.::apply — Updates all values by applying a   to  value.::capacity — Returns the  capacity.::clear — Removes all values.::__construct — Creates a  instance.::contains — Determines  the vector contains given values.:: — Returns a shallow  of the vector.:: — Returns the  of values in the collection.::filter — Creates a  vector using a callable to determine which values to .::find — Attempts to find a value'

       

      • Supports array syntax (square brackets).

      • Uses less overall memory than an array for the same number of values.

      • Automatically frees allocated memory when its size drops low enough.

      • Capacity does not have to be a power of 2.

      • get(), set(), push(), pop() are all O(1).

      • 但是 shift(), unshift(), insert() and remove() are all O(n).

    • Deque Class:“双端队列”的缩写,也用于Ds\Queue中,拥有head、tail两个指针。The pointers can “wrap around” the end of the buffer, which avoids the need to move other values around to make room. This makes shift and unshift very fast —  something a Ds\Vector can’t compete with. 其具有以下优缺点:

      • Supports array syntax (square brackets).

      • Uses less overall memory than an array for the same number of values.

      • Automatically frees allocated memory when its size drops low enough.

      • get(), set(), push(), pop(), shift(), and unshift() are all O(1).

      • 但Capacity must be a power of 2.insert() and remove() are O(n).

    • Map Class:键值对的连续集合,几乎与数组相同。键可以是任何类型,但必须是唯一的。如果使用相同的键添加到map中,则将替换值。其拥有以下优缺点:

      • Keys and values can be any type, including objects.

      • Supports array syntax (square brackets).

      • Insertion order is preserved.

      • Performance and memory efficiency is very similar to an array.

      • Automatically frees allocated memory when its size drops low enough.

      • Can’t be converted to an array when objects are used as keys.

    • Pair Class:A pair is used by Ds\Map to pair keys with values.

      Ds\Pair implements JsonSerializable {/* 方法 */public __construct ([ mixed $key [, mixed $value ]] )
      }

    • Set Class唯一值序列。 This implementation uses the same hash table as Ds\Map, where values are used as keys and the mapped value is ignored.其拥有以下优缺点:

      • Values can be any type, including objects.

      • Supports array syntax (square brackets).

      • Insertion order is preserved.

      • Automatically frees allocated memory when its size drops low enough.

      • add(), remove() and contains() are all O(1).

      • 但Doesn’t support push(), pop(), insert(), shift(), or unshift(). get() is O(n) if there are deleted values in the buffer before the accessed index, O(1) otherwise.

    • Stack Class: “last in, first out”集合,只允许在结构顶部进行访问和迭代。

      Ds\Stack implements Ds\Collection {/* 方法 */public void allocate ( int $capacity )public int capacity ( void )public void clear ( void )public Ds\Stack copy ( void )public bool isEmpty ( void )public mixed peek ( void )public mixed pop ( void )public void push ([ mixed $...values ] )public array toArray ( void )
      }

    • Queue Class“first in, first out”集合,只允许在结构前端进行访问和迭代。

      Ds\Queue implements Ds\Collection {/* Constants */const int MIN_CAPACITY = 8 ;/* 方法 */public void allocate ( int $capacity )public int capacity ( void )public void clear ( void )public Ds\Queue copy ( void )public bool isEmpty ( void )public mixed peek ( void )public mixed pop ( void )public void push ([ mixed $...values ] )public array toArray ( void )
      }

    • PriorityQueue Class:优先级队列与队列是非常相似的,但值以指定的优先级被推入队列,优先级最高的值总是位于队列的前面,同优先级元素“先入先出”顺序任然保留。在一个PriorityQueue上递代是具有破坏性的,相当于连续弹出操作直到队列为空。Implemented using a max heap.

      Ds\PriorityQueue implements Ds\Collection {/* Constants */const int MIN_CAPACITY = 8 ;/* 方法 */public void allocate ( int $capacity )public int capacity ( void )public void clear ( void )public Ds\PriorityQueue copy ( void )public bool isEmpty ( void )public mixed peek ( void )public mixed pop ( void )public void push ( mixed $value , int $priority )public array toArray ( void )
      }

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