封装函数,找出数组 arr 中重复出现过的元素.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    //封装函数,找出数组 arr 中重复出现过的元素.
    //示例: console.log(duplicates( [1, 2, 4, 4, 3, 3, 1, 5, 3] ));
    //返回结果: 1, 3, 4
    function duplicates(arr) {
        arr.sort(function (n, m) {
            return n - m;
        });
        var subArr = [];
        for (var i = 0; i < arr.length; i++) {
            if (arr[i] == arr[i + 1]) {
                subArr.push(arr[i]);
            }
        }

        subArr.sort(function (n, m) {
            return n - m;
        });

        for (var i = 0; i < subArr.length; i++) {
            if (subArr[i] === subArr[i + 1]) {
                subArr.splice(i, 1);
                i--;
            }
        }
        return subArr;
    }
    console.log(duplicates([1, 2, 4, 4, 3, 3, 1, 5, 3]))
</script>
</body>
</html>

posted on 2019-01-09 09:09 猛兽阅读(612) 评论(0) 编辑收藏举报