JavaScript練習題# Day03 作業

// 創建對象let myObject = new Object(); myObject.name = "yushuangjian"; myObject.age = 20;console.log(myObject)const oStudent1 = {name:'yushuangjiang',age:20,getUserName:function(){return name;} }; console.log(oStudent1.name); //yushuangjiangconsole.log(typeof oStudent1); //objectconsole.log(typeof null); //object//創建數組 Arrayconst a1 = new Array(); const a2 = []; console.log(typeof a1+"\n"+typeof a2) //object object console.log(a2 instanceof Array);console.log(a2[0]); //undefined a2[0]=1;a2[1]=1.5;a2[2]="余雙江";a2[3]=true;a2[8]=321356; console.log(a2);const a3 = [1,5,"余雙江",false,261];console.log(a3);const avengers = ["小紅","小明","小剛"]; delete avengers[2]; console.log(avengers)const number1 = [1,2,3,4]; let a = number1[0]; let b = number1[1]; let c = number1[2]; let d = number1[3];console.log(`a=${a},b=${b},c=${c}`) const [a,b,c,d] = [1,2,3,4]; //結構語法 console.log(`a=${a},b=${b},c=${c}`)const [a,b] = ["sad",5,6,8,5]; console.log(`a=${a},b=${b}`)const avengers = ["小紅","小明","小剛"]; console.log(avengers.length); avengers.length = 2; console.log(avengers); const avengers = [123,"小明","小剛"]; avengers.pop(); //.pop()； 方法，刪除數組的最后一個元素 avengers.shift(); //.shift();方法，刪除數組的第一個元素 avengers.push("156");//push();方法，將一個新值添加到數組的結尾 avengers.unshift("余"); //log();方法 console.log(avengers);const avengers = ["小紅","小明","小剛"]; const heroes = ["李華","王剛","趙宏"]; const ah = avengers.concat(heroes); console.log(ah); //ES6 擴展運算符 const avengers = ["小紅","小明","小剛"]; const heroes = ["李華","王剛","趙宏"]; const ah = [...avengers, ...heroes]; console.log(ah);const avengers = ["小紅","小明","小剛"]; const av1 = avengers.join(); console.log(av1); const av2 = avengers.join('+'); console.log(av2);const avengers = ["小紅","小明","小剛"]; console.log(avengers.slice(1,2)); console.log(avengers);const avengers = ["小紅","小明","小剛"]; console.log(avengers.splice(1,2,'ysj',1)); //切片出來，并操作原數組 console.log(avengers);const number1 = [1,2,3,5,8,6,2,45,2,1]; console.log(number1.sort()); //sort();方法，將數組按字母順序進行排序 console.log(number1);const str = ['a','b','h','z']; console.log(str.sort()); console.log(str);const str = ['a','b','h','z']; console.log(str.indexOf('z')); console.log(str.indexOf('b',2)); //后面帶值表示從指定位數開始查詢 console.log(str.includes("a")); //同上，可在后面加參數//多維數組 const ma = [[1,2,3],[4,5,6]]; console.log(ma); console.log(ma[0][0]); console.log(ma[1][2]);//變量聲明 //var >ES5 不建議用 會加入全局變量 //let >ES6 不會加入全局變量 //const>ES6 一般用//循環 for...in // for...or 可迭代的 //集合 set const oSet = new Set(); oSet.add(1); oSet.add(2); oSet.add(3); oSet.add(4); oSet.add(5); console.log(oSet);const list1 = new Set([1,2,3,4,5,6]); console.log(list1);const list2 = new Set(["hello"]); console.log(list2);const list3 = new Set().add(`the`).add(`quick`).add(`brown`).add(`fox`); console.log(list3.size); console.log(list3);list3.size = 2; //集合中只讀，長度不修改 console.log(list3);const list3 = new Set().add(`the`).add(`quick`).add(`brown`).add(`fox`); console.log(list3.has("fox")); //查找，有則true const list3 = new Set().add(`the`).add(`quick`).add(`brown`).add(`fox`); console.log(list3.delete('fox')); //刪除集合中的指定元素 console.log(list3); list4 = list3; console.log(list4.clear());//集合轉換為數組 const list3 = new Set().add(`the`).add(`quick`).add(`brown`).add(`fox`); const a = Array.from(list3); console.log(a);const list3 = new Set().add(`the`).add(`quick`).add(`brown`).add(`fox`); const a = [...list3]; console.log(a);//去掉數組中的重復元素 const oArray1 = [1,2,5,2,5,1,3,6,5,2,2,3]; const oSet1 = new Set(oArray1) console.log(oSet1) const oArray2 = [...oSet1]; console.log(oArray2); // WeakSet弱集合 里面的數據類型只能是引用類型 let oArray1 = [1,2,5,2,5,1,3,6,5,2,2,3]; const strong = new Set(); strong.add(oArray1); oArray1 = null; console.log([...strong][0]); console.log(strong.has(oArray1));let oArray1 = [1,2,5,2,5,1,3,6,5,2,2,3]; const weak = new WeakSet(); weak.add(oArray1); oArray1 = null; console.log([...weak][0]); console.log(weak.has(oArray1));//Map 鍵值對 const oMap = new Map(); oMap.set(1,'I'); oMap.set(2,`II`).set(3,`III`).set(4,`V`).set(5,`IV`); console.log(oMap); console.log(oMap.size); console.log(oMap.get(5)); console.log() console.log(oMap.has(5)); console.log(oMap.delete(5)); console.log(oMap.clear());const oMap = new Map(); oMap.set(1,'I'); oMap.set(2,`II`).set(3,`III`).set(4,`V`).set(5,`IV`); const oArray1 = [...oMap]; console.log(oArray1); //多維數組裝換為一維數組 //方法一：使用apply實現 const oArray2 = [].concat.apply([],oArray1) console.log(oArray2);

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