// Q1. make a string out of an array
{
const fruits = ["apple", "banana", "orange"];
const result = fruits.join(" ");
console.log(result, typeof result);
}
// Q2. make an array out of a string
{
const fruits = "🍎, 🥝, 🍌, 🍒";
const result = fruits.split(",", 3);
console.log(result, typeof result);
}
// Q3. make this array look like this: [5, 4, 3, 2, 1]
{
const array = [1, 2, 3, 4, 5];
const result = array.reverse();
console.log(result, typeof result);
}
// Q4. make new array without the first two elements @@@@@
const array = [1, 2, 3, 4, 5];
const result = array.slice(2, array.length);
console.log(result);
console.log(array);
}
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),
];
// Q5. find a student with the score 90
{
const result = students.find((student) => student.score === 90);
console.log(result);
}
// Q6. make an array of enrolled students
{
const result = students.filter((student) => student.enrolled === true);
console.log(result);
}
// Q7. make an array containing only the students' scores
// result should be: [45, 80, 90, 66, 88]
{
const result = students.map((student) => student.score);
console.log(result);
}
// Q8. check if there is a student with the score lower than 50
{
const result = students.some((student) => student.score < 50);
console.log(result);
}
// Q9. compute students' average score @@@@@
{
const result = students.reduce((acc, cur) => {
console.log(acc + cur.score);
return acc + cur.score; // 초기값은 0이며 return 값이 acc 인 매개변수로로 들어감
}, 0);
console.log(result / students.length); // 73.8점
}
// Q10. make a string containing all the scores
// result should be: '45, 80, 90, 66, 88'
{
const result = students.map((student) => student.score);
console.log(result);
const result2 = result.toString();
const result3 = result.join();
console.log(result2);
console.log(result3);
}
// Bonus! do Q10 sorted in ascending order
// result should be: '45, 66, 80, 88, 90'
{
const result = students
.map((student) => student.score)
.sort((a, b) => a - b) // sort로 배열 정렬 후 join으로 문자열 변환
.join();
console.log(result);
}
