js取两个数组的交集|差集|并集|补集|去重示例代码

http://www.jb51.net/article/40385.htm

代码如下:
/**
* each是一个集合迭代函数，它接受一个函数作为参数和一组可选的参数
* 这个迭代函数依次将集合的每一个元素和可选参数用函数进行计算，并将计算得的结果集返回
{%example
<script>
var a = [1,2,3,4].each(function(x){return x > 2 ? x : null});
var b = [1,2,3,4].each(function(x){return x < 0 ? x : null});
alert(a);
alert(b);
</script>
%}
* @param {Function} fn 进行迭代判定的函数
* @param more ... 零个或多个可选的用户自定义参数
* @returns {Array} 结果集，如果没有结果，返回空集
*/
Array.prototype.each = function(fn){
fn = fn || Function.K;
var a = [];
var args = Array.prototype.slice.call(arguments, 1);
for(var i = 0; i < this.length; i++){
var res = fn.apply(this,[this[i],i].concat(args));
if(res != null) a.push(res);
}
return a;
};

--------------------------------------------------------------------------------------------

/**

 * Array.prototype.[method name] allows you to define/overwrite an objects method

 * needle is the item you are searching for

 * this is a special variable that refers to "this" instance of an Array.

 * returns true if needle is in the array, and false otherwise

 */

Array.prototype.contains = function ( needle ) {

  for (i in this) {

    if (this[i] == needle) return true;

  }

  return false;

}

-------------------------------------------------------------------------------------------
/**
* 得到一个数组不重复的元素集合<br/>
* 唯一化一个数组
* @returns {Array} 由不重复元素构成的数组
*/
Array.prototype.uniquelize = function(){
var ra = new Array();
for(var i = 0; i < this.length; i ++){
if(!ra.contains(this[i])){
ra.push(this[i]);
}
}
return ra;
};
----------------------------------------------------------------------------
/**
* 求两个集合的补集
{%example
<script>
var a = [1,2,3,4];
var b = [3,4,5,6];
alert(Array.complement(a,b));
</script>
%}
* @param {Array} a 集合A
* @param {Array} b 集合B
* @returns {Array} 两个集合的补集
*/
Array.complement = function(a, b){
return Array.minus(Array.union(a, b),Array.intersect(a, b));
};
-------------------------------------------------------------------------------------------
/**
* 求两个集合的交集
{%example
<script>
var a = [1,2,3,4];
var b = [3,4,5,6];
alert(Array.intersect(a,b));
</script>
%}
* @param {Array} a 集合A
* @param {Array} b 集合B
* @returns {Array} 两个集合的交集
*/
Array.intersect = function(a, b){
return a.uniquelize().each(function(o){return b.contains(o) ? o : null});
};
-----------------------------------------------------------------------------------
/**
* 求两个集合的差集
{%example
<script>
var a = [1,2,3,4];
var b = [3,4,5,6];
alert(Array.minus(a,b));
</script>
%}
* @param {Array} a 集合A
* @param {Array} b 集合B
* @returns {Array} 两个集合的差集
*/
Array.minus = function(a, b){
return a.uniquelize().each(function(o){return b.contains(o) ? null : o});
};
----------------------------------------------------------------------------------
/**
* 求两个集合的并集
{%example
<script>
var a = [1,2,3,4];
var b = [3,4,5,6];
alert(Array.union(a,b));
</script>
%}
* @param {Array} a 集合A
* @param {Array} b 集合B
* @returns {Array} 两个集合的并集
*/
Array.union = function(a, b){
return a.concat(b).uniquelize();
};