哈希表在php中的使用

<?php

class hashTable

{

    private $collection;

    private $size = 100;

    //初始化哈希表的大小

    public function __construct($size='')

    {

        $bucketsSize = is_int($size)?$size:$this->size;

        $this->collection = new SplFixedArray($bucketsSize);

    }

    //生成散列值，作为存储数据的位置

    private function _hashAlgorithm($key)

    {

        $length = strlen($key);

        $hashValue = 0;

        for($i=0; $i<$length; $i++) {

            $hashValue += ord($key[$i]);

        }

        return ($hashValue%($this->size));

    }

    //在相应的位置存储对应的值

    public function set($key, $val)

    {

        $index = $this->_hashAlgorithm($key);

        $this->collection[$index] = $val;

    }

    //根据键生成散列值，进而找到对应的值

    public function get($key)

    {

        $index = $this->_hashAlgorithm($key);

        return $this->collection[$index];

    }

    //删除某个值,成功返回1，失败返回0

    public function del($key)

    {

        $index = $this->_hashAlgorithm($key);

        if(isset($this->collection[$index])) {

            unset($this->collection[$index]);

            return 1;

        } else {

            return 0;

        }

    }

    //判断某个值是否存在，存在返回1， 不存在返回0

    public function exist($key)

    {

        $index = $this->_hashAlgorithm($key);

        if($this->collection[$index]){

            return 1;

        } else {

            return 0;

        }

    }

    //返回key的个数

    public function size()

    {

        $size = 0;

        $length = count($this->collection);

        for($i=0; $i<$length; $i++) {

            if($this->collection[$i]) {

                $size++;

            }

        }

        return $size;

    }

    //返回value的序列

    public function val()

    {

        $size = 0;

        $length = count($this->collection);

        for($i=0; $i<$length; $i++) {

            if($this->collection[$i]) {

                echo $this->collection[$i]."<br />";

            }

        }

    }

    //排序输出

    public function sort($type=1)

    {

        $length = count($this->collection);

        $temp = array();

        for($i=0; $i<$length; $i++) {

            if($this->collection[$i]) {

                $temp[] = $this->collection[$i];

            }

        }

        switch ($type) {

            case 1:

                //正常比较

                sort($temp, SORT_REGULAR);

                break;

            case 2:

                //按照数字比较

                sort($temp, SORT_NUMERIC);

                break;

            //按照字符串进行比较

            case 3:

                sort($temp, SORT_STRING);

                break;

            //根据本地字符编码环境进行比较

            case 4:

                sort($temp, SORT_LOCALE_STRING);

                break;

        }

        echo "<pre>";

        print_r($temp);

    }

    //逆序输出

    public function rev($type=1)

    {

        $length = count($this->collection);

        $temp = array();

        for($i=0; $i<$length; $i++) {

            if($this->collection[$i]) {

                $temp[] = $this->collection[$i];

            }

        }

        switch ($type) {

            case 1:

                //正常比较

                rsort($temp, SORT_REGULAR);

                break;

            case 2:

                //按照数字比较

                rsort($temp, SORT_NUMERIC);

                break;

            //按照字符串进行比较

            case 3:

                rsort($temp, SORT_STRING);

                break;

            //根据本地字符编码环境进行比较

            case 4:

                rsort($temp, SORT_LOCALE_STRING);

                break;

        }

        echo "<pre>";

        print_r($temp);

    }

}

//简单的测试

$list = new hashTable(200);

$list->set("zero", "zero compare");

$list->set("one", "first test");

$list->set("two", "second test");

$list->set("three", "three test");

$list->set("four", "fouth test");

echo $list->val();

echo "after sorted : <br />";

$list->rev(3);