/**冒泡排序的思想
让数组中的当前项和后一项进行比较，如果当前项比后一项大，则两项交换位置(让大的靠后)
**/
let ary = [53,45,23,46,37,25,12,10,20,30,40,50]
function bubble(ary){
var temp = null;
//外层循环i控制比较的轮数
for(let i = 0; i < ary.length-1;i++){
var cur = ary[i];
//里层循环控制每一轮比较的次数
for(let j=0;j<ary.length-1-i;j++){
if(ary[j] > ary[j+1]){
//当前项大于后一项
temp= ary[j];
ary[j] =ary[j+1];
ary[j+1] =temp
}
}
}
return ary;
}
console.log(bubble(ary));
数组去重
Array.prototype.myUnique = functionmyUnique (){
var obj = {};
var arr = this.slice(0);
for(var i = 0; i<arr.length; i++){
var cur = arr[i];
if(typeof obj[cur] !== "undefined"){
arr[i] = arr[arr.length-1];
arr.length--;
i--;
continue;
}
obj[cur] = cur;
}
obj = null;
return arr;
}
let ary = [12,23,12,13,13,12,23,14,8];
let newarr = ary.myUnique().sort((a,b)=>a -b);
console.log(newarr);
console.log(ary);
// 原型上添加 支持链式调用
Array.prototype.myUnique = function(){
var obj = {};
for(let i = 0; i < this.length; i++){
var cur = this[i];
if(typeof obj[cur] !== 'undefined'){
this[i] = this[this.length-1];
this.length--;
i--;
continue;
}
obj[cur] = cur;
}
obj = null;
return this;
};
任意数求和
functionsum (){
var total = null;
for(var i =0;i< arguments.length;i++){
var item = Number(arguments[i]);
if(isNaN(item))continue;
total+=item;
}
return total;
}
let total = sum(10, 20, 30, '40', 'AA');
console.log(total);
url截取参数
<script>
function queryURLParams(url) {
//创建A标签(A元素对象)来获取到问号参数和哈希值
let link = document.createElement("a");
link.href = url;
console.log(link)
let askText = link.search.substr(1),
polText = link.hash.substr(1),
obj = {};
polText ? obj['HASH'] = polText : null;
if(askText){
let arr = askText.split(/(?:&|=)/g);
console.log(arr);
for(let i = 0; i<arr.length;i+=2){
obj[arr[i]] = arr[i+1];
}
}
return obj;
}
let result = queryURLParams('http://zhufengpeixun.cn/?lx=1&name=js&from=baidu#video');
console.log(result);
const url = 'http://example.com/index.html?a=1&b=2&c=3&d';
</script>
手写深拷贝
/**
* 深拷贝
*/
const obj1 = {
age: 20,
name: 'xxx',
address: {
city: 'beijing'
},
arr: ['a', 'b', 'c']
}
const obj2 = deepClone(obj1)
obj2.address.city = 'shanghai'
obj2.arr[0] = 'a1'
console.log(obj1.address.city)
console.log(obj1.arr[0])
/**
* 深拷贝
* @param {Object} obj 要拷贝的对象
*/
function deepClone(obj = {}) {
if (typeof obj !== 'object' || obj == null) {
// obj 是 null ，或者不是对象和数组，直接返回
return obj
}
// 初始化返回结果
let result
if (obj instanceof Array) {
result = []
} else {
result = {}
}
for (let key in obj) {
// 保证 key 不是原型的属性
if (obj.hasOwnProperty(key)) {
// 递归调用！！！
result[key] = deepClone(obj[key])
}
}
// 返回结果
return result
}
