PHP如何写哈希表,PHP实现哈希表

//一个简单的哈希表实现。。。。

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

$hashValue += ord($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

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

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

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

}

}

}

//排序输出

public function sort($type=1)

{

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

$temp = array();

for($i=0; $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 "

";

print_r($temp);

}

//逆序输出

public function rev($type=1)

{

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

$temp = array();

for($i=0; $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 "

";

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 :
";

$list->rev(3);