无涯教程-Javascript - filter()函数 JavaScript array.filter()方法满足条

JavaScript array.filter()方法满足条件的所有元素集合，返回一个新数组。

filter() - 语法

array.filter(callback[, thisObject]);

callback - 用于测试数组的每个元素。
thisObject - 要在执行回调时用作的对象。

filter() - 返回值

返回创建的数组。

filter() - 相容性

此方法是ECMA-262标准的JavaScript扩展；因此，它可能不存在于该标准的其他实现中。要使其工作，您需要在脚本顶部添加以下代码。

if (!Array.prototype.filter) {
   Array.prototype.filter=function(fun /*, thisp*/) {
      var len=this.length;
      if (typeof fun != "function")
      throw new TypeError();
  </span><span class="kwd">var</span><span class="pln"> res</span><span class="pun">=</span><span class="kwd">new</span><span class="pln"> </span><span class="typ">Array</span><span class="pun">();</span><span class="pln">
  </span><span class="kwd">var</span><span class="pln"> thisp</span><span class="pun">=</span><span class="pln">arguments</span><span class="pun">[</span><span class="lit">1</span><span class="pun">];</span><span class="pln">
  </span><span class="kwd">for</span><span class="pln"> </span><span class="pun">(</span><span class="kwd">var</span><span class="pln"> i</span><span class="pun">=</span><span class="lit">0</span><span class="pun">;</span><span class="pln"> i </span><span class="pun">&lt;</span><span class="pln"> len</span><span class="pun">;</span><span class="pln"> i</span><span class="pun">++)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
     </span><span class="kwd">if</span><span class="pln"> </span><span class="pun">(</span><span class="pln">i </span><span class="kwd">in</span><span class="pln"> </span><span class="kwd">this</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
        </span><span class="kwd">var</span><span class="pln"> val</span><span class="pun">=</span><span class="kwd">this</span><span class="pun">[</span><span class="pln">i</span><span class="pun">];</span><span class="pln">   </span><span class="com">//in case fun mutates this</span><span class="pln">
        </span><span class="kwd">if</span><span class="pln"> </span><span class="pun">(</span><span class="pln">fun</span><span class="pun">.</span><span class="pln">call</span><span class="pun">(</span><span class="pln">thisp</span><span class="pun">,</span><span class="pln"> val</span><span class="pun">,</span><span class="pln"> i</span><span class="pun">,</span><span class="pln"> </span><span class="kwd">this</span><span class="pun">))</span><span class="pln">
        res</span><span class="pun">.</span><span class="pln">push</span><span class="pun">(</span><span class="pln">val</span><span class="pun">);</span><span class="pln">
     </span><span class="pun">}</span><span class="pln">
  </span><span class="pun">}</span><span class="pln">
  </span><span class="kwd">return</span><span class="pln"> res</span><span class="pun">;</span><span class="pln">

};
}

filter() - 示例

<html>
   <head>
      <title>JavaScript Array filter Method</title>
   </head>
   
   <body>   
      <script type="text/javascript">
         if (!Array.prototype.filter) {
            Array.prototype.filter=function(fun /*, thisp*/) {
               var len=this.length;
            
               if (typeof fun != "function")
               throw new TypeError();
            
               var res=new Array();
               var thisp=arguments[1];
            
               for (var i=0; i < len; i++) {
                  if (i in this) {
                     var val=this[i];   //in case fun mutates this
                     if (fun.call(thisp, val, i, this))
                     res.push(val);
                  }
               }
               return res;
            };
         }
         function isBigEnough(element, index, array) {
            return (element >= 10);
         }
         var filtered =[12, 5, 8, 130, 44].filter(isBigEnough);
         document.write("Filtered Value : " + filtered ); 
      </script>      
   </body>
</html>

运行上面代码输出

Filtered Value : 12,130,44

无涯教程-Javascript - filter()函数

filter() - 语法

filter() - 返回值

filter() - 相容性

filter() - 示例

参考链接