VIDEO
동영상 수강 및 본문 읽기 전 아래 좌표 먼저 풀어보세요.
https://drive.google.com/file/d/1smYHFS5fbgdyGHjBmXx2P-IyY3VWJ9tm/view
※ 특정 메서드가 배열 자체를 변화시키는지 아니면 새 배열 생성하는지 여부에 주의 !!
02:04
Q1. make a string out of an array
arr .join() : (array → string) 변환.
// Q1. make a string out of an array
{
const fruits = ['apple', 'banana', 'orange'];
const res1 = fruits.join();
console.log(res1);
const res2 = fruits.join('|');
console.log(res2);
}
결과보기
05:07
Q2. make an array out of a string
str .split() : (string → array) 변환.
// Q2. make an array out of a string
{
const fruits = 'apple, kiwi, banana, cherry';
const res1 = fruits.split(',');
console.log(res1); // ["apple", " kiwi", " banana", " cherry"]
const res2 = fruits.split(',', 2);
console.log(res2); // ["apple", " kiwi"]
const res3 = fruits.split();
console.log(res3); // ["apple, kiwi, banana, cherry"]
}
결과보기
07:33
Q3. make this array look like this: [5, 4, 3, 2, 1]
arr.reverse() : 배열 자체의 순서 뒤집기
// Q3. make this array look like this: [5, 4, 3, 2, 1]
{
const array = [1, 2, 3, 4, 5];
const res = array.reverse();
console.log(res); // [5, 4, 3, 2, 1]
console.log(array); // [5, 4, 3, 2, 1]
}
결과보기
08:32
Q4. make new array without the first two elements
arr.splice() : 배열 자체는 변화 O
arr.slice() : 배열 자체는 변화 X (∴ 이것을 사용해야 함.)
// Q4. make new array without the first two elements
{
const array = [1, 2, 3, 4, 5];
/*
const res1 = array.splice(0, 2);
console.log(res1); // [1, 2]
console.log(array); // [3, 4, 5]
*/
const res2 = array.slice(2, 5);
console.log(res2); // [3, 4, 5]
console.log(array); // [1, 2, 3, 4, 5]
}
결과보기
class Student {
constructor(name, age, enrolled, score) {
this.name = name;
this.age = age;
this.enrolled = enrolled;
this.score = score;
}
}
const students = [
new Student('A', 29, true, 45),
new Student('B', 28, false, 80),
new Student('C', 30, true, 90),
new Student('D', 40, false, 66),
new Student('E', 18, true, 88),
];
11:48
Q5. find a student with the score 90
arr.find() :
// Q5. find a student with the score 90
{
/*
const res = students.find(function (student,index) {
// console.log(student,index);
return student.score === 90;
});
*/
const res = students.find((student) => student.score === 90);
console.log(res);
}
결과보기
18:05
Q6. make an array of enrolled students
// Q6. make an array of enrolled students
{
}
// Q7. make an array containing only the students' scores
// result should be: [45, 80, 90, 66, 88]
{
}
// Q8. check if there is a student with the score lower than 50
{
}
// Q9. compute students' average score
{
}
// Q10. make a string containing all the scores
// result should be: '45, 80, 90, 66, 88'
{
}
// Bonus! do Q10 sorted in ascending order
// result should be: '45, 66, 80, 88, 90'
{
}
