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HomeWeb Front-endJS TutorialJavaScript 删除数组重复值(去重)的两种方法

javascript数组去重方法一:

Array类型并没有提供去重复的方法,如果要把数组的重复元素干掉,那得自己想办法:

方法一:利用indexOf方法;

<code class="language-javascript">var aa=[1,3,5,4,3,3,1,4]
function arr(arr) {
  var result=[]
  for(var i=0; i<arr.length i if result.push console.log arr></arr.length></code>

 

javascript数组去重方法二:

<code class="language-javascript">function unique(arr) {
  var result = [], isRepeated;
  for (var i = 0, len = arr.length; i </code>

方法二,总体思路是把数组元素逐个搬运到另一个数组,搬运的过程中检查这个元素是否有重复,如果有就直接丢掉。从嵌套循环就可以看出,这种方法效率极低。我们可以用一个hashtable的结构记录已有的元素,这样就可以避免内层循环。恰好,在Javascript中实现hashtable是极为简单的,改进如下:

<code class="language-javascript">function unique(arr) {
  var result = [], hash = {};
  for (var i = 0, elem; (elem = arr[i]) != null; i++) {
    if (!hash[elem]) {
      result.push(elem);
      hash[elem] = true;
    }
  }
  return result;
}</code>

以上是文章全部内容,希望对码农有所帮助。

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