2-04.Array.html

<!DOCTYPE html>
<html>
<head>
  <title>Document</title>
</head>
<body>
  <div id="div1"></div>
  <script>
    //toString()
    // var fruits = ["Banana", "Orange", "Apple"];
    // console.log(fruits.toString());

    // //join()
    // console.log(fruits.join(","));
    // var txt = "Banana<br>";
    // txt += "Orange<br>";
    // txt += "Apple<br>";

    // var arr = [];
    // arr.push("Banana");
    // arr.push("Orange");
    // arr.push("Apple");

    // // document.getElementById("div1").innerHTML = txt;
    // document.getElementById("div1").innerHTML = arr.join("<br>");

    // //pop()
    // //배열의 가장 마지막 element를 제거
    // //pop() 하면, 제거된 element 리턴 함.

    // var str = fruits.pop();
    // console.log(str);
    // console.log(fruits);

    // //push()
    // //배열에 마지막에 새 element 추가
    // fruits.push("Kiwi");
    // console.log(fruits);

    // //shift()
    // //배열의 첫번째 element제거 함
    // //shift() 리턴으로 제거된 element 반환
    // var str = fruits.shift();
    // console.log(str);
    // console.log(fruits);

    // //unshift()
    // //배열의 첫번째에 새 element 추가
    // fruits.unshift("Lemon");
    // console.log(fruits);

    // fruits[0] = "Banana";

    // console.log(fruits);

    // fruits[fruits.length-1] = "Lemon";
    // console.log(fruits);

    //splice()
    //첫번째 - 시작위치
    //두번째 - 삭제할 element 수

    var fruits = ["Banana", "Orange", "Apple"];
    fruits.splice(1,0,"Lemon","Kiwi");
    console.log(fruits);

    //concat()
    // var myBoys = ["Eunhyeok"];
    // var myGirls = ["Eunseo", "Eunsol"];
    // var myChildren = myBoys.concat(myGirls);
    // console.log(myChildren);

    //slice()
    // var fruits2 = fruits.slice(1);
    // console.log(fruits2);

    //sort()
    console.log(fruits.sort());

    var points = [40, 100, 70, 21, 99];
    // console.log(points.sort());
    points.sort(function(a, b){
      // if(a > b) {
      //   return 3;
      // }else if(a < b) {
      //   return -3;
      // }else {
      //   return 0;
      // }
      return b-a;
    });

    console.log(points);
    points.reverse();
    console.log(points);

    var persons = [
      {name:"유재석", point:78, city:"서울"},
      {name:"김종국", point:92, city:"서울"},
      {name:"양세찬", point:76, city:"제주"},
      {name:"하하", point:81, city:"서울"}
    ];

    // persons.sort(function(a,b){
    //   // if(a.point > b.point) {
    //   //   return -1;
    //   // }else if(a.point < b.point) {
    //   //   return 1;
    //   // }else {
    //   //   return 0;
    //   // }

    //   return a.point > b.point ? -1 : a.point < b.point ? 1 : 0;
    // });

    console.log(persons);

    //filter()
    var pass = persons.filter(function(person){
      return person.point > 80;
    });

    console.log(pass);

    var jeju = persons.filter(function(person){
      return person.city == "제주";
    });

    console.log(jeju);

    var jeju = [];

    for(var i=0 ; i<persons.length ; i++) {
      if(persons[i].city == "제주") {
        jeju.push(persons[i]);
      }
    }

    console.log(jeju);

    //reduce
    // var total = 0;
    var arr1 = [1,2,3,4];
    // for(var x of arr1) {
    //   total += x;
    // }

    // console.log(total);

    //reduce
    //accumulator - 누산기 
    //currentValue - 배열 읽으면서 현재값
    //

    var total = arr1.reduce(function(a,c,i,arr){
      return a + c;
    });

    console.log(total);


    //map
    var userList = [
      {firstName:"재석", lastName:"유", email:"yu@gmail.com"},
      {firstName:"종국", lastName:"김", email:"kim@gmail.com"},
      {firstName:"세찬", lastName:"양", email:"yang@gmail.com"},
      {firstName:"석진", lastName:"지", email:"ji@gmail.com"}
    ];

    var userList2 = userList.map(function(user){
      return {fullName:user.lastName + user.firstName, firstName:user.firstName, lastName:user.lastName}
    });

    console.log(userList2);







  </script>
</body>
</html>