# 드림코딩 by 엘리 - 유용한 10가지 배열 함수들 - 퀴즈 정답

bangina·2020년 6월 26일
0

정답은 아니고 혼자 풀어본 코드이니 아 이렇게도 푸는구나~하고 참조해주세요!
정확한 답은 깨끗한 엘리님의 코드로 확인🌞

자바스크립트 9. 유용한 10가지 배열 함수들. Array APIs 총정리 | 프론트엔드 개발자 입문편 ( JavaScript ES6)

<script>
// Q1. make a string out of an array
const fruits = ['apple', 'banana', 'orange'];
const fruitsString = fruits.toString();
console.log(fruitsString);
console.log(fruits.join());

// Q2. make an array out of a string
const fruits2 = '🍎, 🥝, 🍌, 🍒';
const fruitsArray = fruits2.split(",");
console.log(fruitsArray);

// Q3. make this array look like this: [5, 4, 3, 2, 1]
const array = [1, 2, 3, 4, 5];
const arrayReverse = array.reverse();
console.log(arrayReverse);

// Q4. make new array without the first two elements
const array2 = [1, 2, 3, 4, 5];
const array3 = array2.slice(2, 5);
console.log(array3);

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 student90 = students.filter(student => student.score === 90);
console.log(student90[0].name);

// Q6. make an array of enrolled students
let enrolledArray = [];
const enrolledStudents = students.filter(student => student.enrolled === true).forEach(e => enrolledArray.push(e
.name));
console.log(enrolledArray);

// Q7. make an array containing only the students' scores
// result should be: [45, 80, 90, 66, 88]
let scoresArray = [];
students.forEach(student => scoresArray.push(student.score));
console.log(scoresArray);

// Q8. check if there is a student with the score lower than 50
let lowScoreStudents = students.filter(student => student.score < 50);
console.log(lowScoreStudents, 1);

if (lowScoreStudents == false) {
console.log("There is no student with the score lower than 50");
} else {
console.log("There are students with the score lower than 50");
}

// Q9. compute students' average score
// const scoreSum = scoresArray.forEach(score => score);
let scoreSum = 0;
for (let i = 0; i < scoresArray.length; i++) {
scoreSum += scoresArray[i];
}
const averageScore = scoreSum / students.length;
console.log(averageScore);

// Q10. make a string containing all the scores
// result should be: '45, 80, 90, 66, 88'
const scoresString = scoresArray.join();
console.log(scoresString);

// Bonus! do Q10 sorted in ascending order
// result should be: '45, 66, 80, 88, 90'
console.log(scoresArray.sort().join());
</script>

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