Python Flask框架全栈开发(网易云课堂)

var arr1=[1,2,3];
var arr2=Array.from(arr1);
arr1.push(4);
alert(arr1);  //1234
alert(arr2);  //123
arr2.push(5);
alert(arr1);  //1234
alert(arr2);  //1235
var arr1=[1,2,3];
var arr2=[...arr1];
arr1.push(4);
alert(arr1);  //1234
alert(arr2);  //123
arr2.push(5);
alert(arr1);  //1234
alert(arr2);  //1235
function show(...arr1){  //直接来复制arguments这个伪数组，让它变成真正的数组，从而拥有数组的方法。
  alert(arr1); //1234
  arr1.push(5);
  alert(arr1); //12345
}
show(1,2,3,4)
var arr1=[1,2,3,4];
var arr2=[];
for(var i=0; i<arr1.length; i++){
  arr2[i]=arr1[i];
}
arr1.push(5);
arr2.push(6);
alert(arr1); //12345
alert(arr2); //12346
 
//或者是json
 
var json1={"name":"鹏哥","age":24,"job":"前端开发"};
var json2={};
for(var name in json1){
  json2[name]=json1[name];
}
alert(JSON.stringify(json1)); //{"name":"鹏哥","age":24,"job":"前端开发"}
alert(JSON.stringify(json2)); //{"name":"鹏哥","age":24,"job":"前端开发"}
json1.a=1;
json2.b=2;
alert(JSON.stringify(json1)); //{"name":"鹏哥","age":24,"job":"前端开发","a":1}
alert(JSON.stringify(json2)); //{"name":"鹏哥","age":24,"job":"前端开发","b":2}
var syb = Symbol('obj');
var person = {
   name :'tino',
   say: function(){
      console.log('hi');
   },
   ok: syb,
   un: undefined
}
var copy = JSON.parse(JSON.stringify(person))
// copy
// {name: "tino"}
var a = {
  name: 'yaodebian',
  info: {
    age: 21,
    weight: 150
  },
  arr: [1, 2, 3]
};
var temp = JSON.stringify(a);
var b = JSON.parse(temp);
a.name = 'I am your father';
a.info.age = 0;
a.arr.push(4);
console.log(a);
console.log(b);
输出结果：
 
{ name: 'I am your father',
  info: { age: 0, weight: 150 },
  arr: [ 1, 2, 3, 4 ] }
{ name: 'yaodebian',
  info: { age: 21, weight: 150 },
  arr: [ 1, 2, 3 ] }