[JavaScript] Array APIs 총정리!! By.Quiz (With. Ellie)
// Q1. make a string out of an array
{
const fruits = ['apple', 'banana', 'orange'];
const result = fruits.join();
console.log(result);
}
// Q2. make an array out of a string
{
const fruits = '🍎, 🥝, 🍌, 🍒';
const result = fruits.split(',');
console.log(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);
}
// Q4. make new array without the first two elements
{
const array = [1, 2, 3, 4, 5];
const result = array.slice(2, 5); //새로운 배열에 저장
// const result = array.splice(0,2) // 기존의 배열 수정
console.log(result);
}
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);
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 result1 = students.some((student) => student.score < 50); // 하나 만족 -> true
const result2 = students.every((student) => student.score >= 50); // 모두 만족 -> true
console.log(result1);
console.log(!result2);
}
// Q9. compute students' average score
{
const result = students.reduce((prev, curr) => {
// console.log('----------');
// console.log(prev);
// console.log(curr);
return prev + curr.score;
}, 0);
console.log(result / students.length);
}
// Q10. make a string containing all the scores
// result should be: '45, 80, 90, 66, 88'
{
const result = students.map((student) => student.score).join();
console.log(result);
}
// Bonus! do Q10 sorted in ascending order
// result should be: '45, 66, 80, 88, 90'
{
const result = students.map((student) => student.score).sort().join();
console.log(result);
}