[강의노트][드림코딩] 배열 Array Quiz 10가지

드림코딩 자바스크립트 배열 강의 노트

 

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);

    console.log(array); // 배열 자체를 변화시킴

}

Q4. make new array without the first two elements

{

    const array = [1, 2, 3, 4, 5];

    const result = array.slice(2, 5); // 2부터 5전까지

    console.log(result);

    // splice는 배열 자체를 변경, but slice는 배열은 그대로

}

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)=>{

        return  student.score === 90;

    });

    console.log(result);

}

Q6. make an array of enrolled students

{

   

}

Q7. make an array containing only the students' scores

result should be: [45, 80, 90, 66, 88]

{

    const result = students.map(e => e.score);

    console.log(result);

}

Q8. check if there is a student with the score lower than 50

{

    const result = students.some(e => e.score < 50);

    console.log(result); // 일부 요소 조건 성립 ||

    const result2 = !students.every(e => e.score >= 50);

    console.log(result2); // 모든 요소 조건 성립 &&

   

}

Q9. compute students' average score

{

}

Q10. make a string containing all the scores

result should be: '45, 80, 90, 66, 88'

{

    const result = students

    .map( s => s.score)

    .filter(score => score >= 50)

    .join();

    console.log(result);

}

Bonus! do Q10 sorted in ascending order

result should be: '45, 66, 80, 88, 90'

{

}