js 数组

 

检测是否为数组

  var arr = [];

  console.log(arr instanceof Array);  // true  

  console.log(Array.isArray(arr)); // true

 

 // 数组排序 

        //  1数组翻转

        var arr = ['pink', 'red', 'blue'];

        arr.reverse();

        console.log(arr);

        // 2 数组排序(冒泡排序)

        var arr2 = [13, 4, 77, 1, 7];

        arr2.sort(function(a, b) {

            // 按升序的顺序排列

            // return a - b;

            // 按降序的顺序排列

            return b - a;

        });

        console.log(arr2);

 

 

数组去重

    // 数组转为字符串

        // 1 toString()

        var arr = [1, 2, 3];

        console.log(arr.toString()); // 1,2,3

        // 2 join (分隔符)

        var arr1 = ['green', 'blue', 'pink'];

        console.log(arr1.join()); // green,blue,pink

        console.log(arr1.join('-')); // green-blue-pink

        console.log(arr1.join('&')); // green&blue&pink