知识点笔记（二维数组排序、统计数组重复个数、）

//统计数组内重复元素的个数
let arr = ["leyi", "leyi", "leyi2", "leyi2", "leyi3", "leyi4", "leyi5"];
let statInfo = [];
arr=arr.sort();//这一步很重要 
for (let i = 0; i < arr.length;) {
    let count = 0;
    for (let j = i; j < arr.length; j++) {
        if (arr[i] == arr[j]) {
            count++;
        }
    }
    statInfo.push({name: arr[i], count: count});
    i += count
}
console.info(statInfo);

//二维数组排序(根据数组里第二个元素排序)
const tdimensionArr = [["c", 3], ["b", 2], ["a", 1], ["e", 5], ["d", 4]];
const sorTdimensionArr = tdimensionArr.sort(((a, b) = > (a[1] - b[1])));
console.info(sorTdimensionArr);

//求输出结果
function Foo() {
    getName = function () {
        console.info(1);
    };
    return this;
}
Foo.getName = function () {
    console.info(2);
};
Foo.prototype.getName = function () {
    console.info(3);
};
var getName = function () {
    console.info(4);
};
function getName() {
    console.info(5);
}

Foo.getName(); //2
getName(); //4
Foo().getName(); //1
getName();//1
new Foo.getName();//2
new Foo().getName();//3
new new Foo().getName();//3

源文章链接 http://www.cnblogs.com/xxcanghai/p/5189353.html