j 数组去重

最新推荐文章于 2024-06-01 07:27:22 发布

原创最新推荐文章于 2024-06-01 07:27:22 发布 · 260 阅读

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本文介绍了五种使用JavaScript实现的数组元素去重方法，包括双层循环检查、字符串化排序去重、对象属性映射等多种实用技巧。

(1)

Array.prototype.unique1 = function() {
    varr =
newArray();
    label:for(vari
 = 0, n = this.length; i < n; i++) {
        for(varx = 0, y = r.length;
 x < y; x++) {
            if(r[x] ==this[i])
 {
                continuelabel;
            }
        }
        r[r.length] =this[i];
    }
    returnr;
};

(2)

Array.prototype.unique2 =function
() {
    returnthis.sort().join(",,").replace(/(,|^)([^,]+)(,,\2)+(,|$)/g,"$1$2$4").replace(/,,+/g,",").replace(/,$/,"").split(",");
};

(3)

Array.prototype.unique3 =function() {
    vartemp = {}, len =
this.length;
    for(vari=0; i < len; i++) 
 {
        vartmp =
this[i];
        if(!temp.hasOwnProperty(tmp)) {
            temp[this[i]] ="my god";
        }
    }
    len = 0;
    vartempArr=[];
    for(vari
intemp) {
        tempArr[len++] = i;
    }
    returntempArr;
}

(4)

Array.prototype.unique4 =function
() {
    vartemp =
newArray();
      this.sort();
      for(var i = 0; i <this.length;
 i++) {
          if(this[i] ==this[i+1])
 {
            continue;
        }
          temp[temp.length]=this[i];
      }
      returntemp;
  
};

(5)

Array.prototype.unique5 =function() {
    varres = [], hash = {};
    for(vari=0, elem; (elem =
this[i]) !=null; i++)  {
        if(!hash[elem])
        {
            res.push(elem);
            hash[elem] =true;
        }
    }
    returnres;
}