js Array 数组方法扩展

//去重复

  Array.prototype.unique = function()

 {

    this.sort();

    var re=[this[0]];

    for(var i = 1; i < this.length; i++)

    {

        if( this[i] !== re[re.length-1])

        {

            re.push(this[i]);

        }

    }

    return re;

 }

 

 //并集

 Array.prototype.union = function(a)

 {

   return this.concat(a).unique();

 

 }

 //差集

 Array.prototype.minus = function(a)

 {

    var result =[];

    var clone = this;

      for(var i=0; i < clone.length; i++)

      {

          var flag = true;

          for(var j=0; j < a.length; j++)

          {  

            if(clone[i] == a[j])  

            flag = false;  

          }  

        if(flag)  

        result.push(clone[i]);

 

      }

 

    return result.unique();

 

 }

// 交集

Array.prototype.intersect = function(b) {

    var result = [];

    var a = this;

    for(var i = 0; i < b.length; i ++) {

        var temp = b[i];

        for(var j = 0; j < a.length; j ++) {

            if(temp === a[j]) {

                result.push(temp);

                break;

            }

        }

    }

    return result.unique();

}