📕 js Array

Q1. Make a String out of a array

// question
const fruits = ["apple", "banna", "orange"];

// answer
const result = fruits.join(",");

Q2. Make an Array out of a string

// question
const fruits = "appale, kiwi, banana, cherry";

// answer
const result = fruits.split();

Q3. Make an Array reverse

// question
const array = [1, 2, 3, 4, 5];

// answer
const result = array.resverse();

Q4. Make new array without the first to elements

// question
const array = [1, 2, 3, 4, 5];

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

Q5. Class Question

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',19,true,88)
]

Q5-1. find a student with the score 90

// answer
const result = students.filiter((item, index, self) => item.score == 90);

Q5-2. make an array containing only the students` scores

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

// answer
const result = students.map((item, index, self) => item.score);

Q5-3. Check if there is a student with the score lower than 50

// answer
const result = students.every((item, index, self) => item.score >= 50);

// or...
const reulst2 = students.some((item, index, self) => item.score < 50);

Q5-4 Compute students` average scroe

// answer
const result =
  students.reduce(
    (accumulator, currentValue, currentIndex, self) =>
      accumulator + currentValue.score,
    0
  ) / students.length;

Q5-5 Make a String containing all the scores

// result should be: '45, 80, 90, 66, 88'
const result = students.map((item, index, self) => item.score).join();

Q5-6 Sort in ascending order

// result should be :'45,66,80,88,90'
const result = students
  .map((item, index, self) => item.score)
  .sort((a, b) => a - b);
  .join()