Get comfortable with JS arrays: exercises for beginners

Just a few exercises that I came up with while tutoring. The goal is to wrap your head around iterating over arrays as a pre-cursor to learning the forEach() and filter() methods in functional JS.

The learner also had some confusion data types in arrays and about Parameters vs Argument so the exercises also reflect those.

1.

let myAlphabet = ['A', 'B', 'C', 'D','E','F', 'G'];

• What is the length of the array?
• Write a function called myAlphabetLength which console.logs the length of the array
• Within the function also use an if-conditional statement that checks if the number of items within the array are less than 4

2.

• Declare a function checkFunc that takes a string and a boolean as parameters
• Call the function using 2 arguments

3.

• Declare and initialize an array called Planets with 5 string values
• console.log each item in the array
• Also console.log the index in each iteration

4.

• Declare and initialize an array called

wowDatatypes

• The array must have 5 different data types (NOT objects)
• Iterate over the array and console.log each item in the array + it’s index and data type in the array

5.

• console.log each item in this array WITHOUT using a for loop

   let myArr = [ 1, 2, 'One', true];

6.

let student1Courses = ['Math', 'English', 'Programming'];
let student2Courses = ['Geography', 'Spanish', 'Programming'];

• Loop over the 2 arrays and if there are any common courses, if so console.log them

7.

let food = ['Noodle', 'Pasta', 'Ice-cream'];
let food = ['Fries', 'Ice-cream', 'Pizza'];

• compare the 2 arrays and find common food if any

8.

let values1= ['Apple', 1, false];
let values2 = ['Fries', 2 ,true];
let values3 = ['Mars', 9, 'Apple'];

• compare the 3 arrays and find any common elements

9.

let furniture = ['Table', 'Chairs','Couch'];

• For each item in this array console.log the letters in each item

Comments

[Ekanem]

Some quick solutions

5)

let myArr = [ 1, 2, 'One', true];

let newArray = myArr.map(item => `This item is ${item}`)
console.log(newArray)

6)

let student1Courses = ['Math', 'English', 'Programming'];
let student2Courses = ['Geography', 'Spanish', 'Programming'];

let commonCourse = [...student1Courses, ...student2Courses].reduce((total, item, index, array) => {
  (array.indexOf(item, index + 1) !== -1 && total.indexOf(item) === -1) ? total.push(item) : null
  return total
}, [])

console.log(commonCourse)

[CamCode]

Hi @kauresss ,
thanks for these exercises!!!
I completed all and they help me to understand better Array

P.s I don't if it's error or not , but in eighth exercise there are same name variable ( values2)

[Kauress]

You're welcome! And thanks for pointing that out, I've corrected it :)

[des3000]

Hello, can you give link to solutions of this exercises? I don't know if I am doing them correctly

[mahmoud]

Some solutions (6)

let student1Courses = ['Math', 'English', 'Programming', 'd'];
let student2Courses = ['Geography', 'd', 'Spanish', 'Programming'];

const filterArray = student1Courses.filter(value => student2Courses.includes(value));

function filterArray(){
const diff = [];
for (let i = 0; i < student1Courses.length; i++) {
const val1 = student1Courses[i];

  for (let j = 0; j < student2Courses.length; j++) {
      const val2 = student2Courses[j];


  if (val2.includes(val1) ) {

    diff.push(val2);
    console.log(diff);

}
  }

}

}

filterArray();

[Roy Frias]

Hello Kauress I was wondering if you can give us a link to the solutions to the problems please , I want to make sure that I am doing them correctly, if you can be so kind.

sincerely Roy Frias

[Kauress]

Hello Roy, sure I'll put up the solutions soon. I'm finishing a 400+ coding exercises workbook after which I'll get some free time

[Roy Frias]

Ah Ok cool, Thank you so much !!

[Manaswini Janaswamy]

can you please share solutions

[scarfada]

**_

Question 4

_**

var wowDatatypes = ['Scarlaty', 26, true, null, ['Cool']]

wowDatatypes.forEach(differentDataType)

function differentDataType(item, index){
console.log('['+index+']'+ " " +item)
}

[scarfada]

**

Question 3

**

var Planets = ['Vênus', 'Marte', 'Mercúrio','Urano','Jupter','Netuno']
Planets.reverse()

Planets.forEach(Interation)

function Interation(item, index){

console.log('['+index+']', item)
}

[brogeby]

Solution to 9)

const furniture = ['Table', 'Chairs', 'Couch']
furniture.forEach(e => console.log(e.split('')))

[aizenmarina]

Hi Kauress, I really liked these exercises because they are just what I needed to practice (and force myself to find out how to solve them! ) Could you please share more? Many thanks! ;)

[Josh Ivan Lanuevo]

Solution # 3

const Planets = ["mercury", "venus", "earth", "mars", "jupiter"];

Planets.forEach((element,index) => console.log(element,index));

[scarfada]

Question 5

let myArr = [ 1, 2, 'One', true];

myArr.filter(passandoPelaArray)

function passandoPelaArray(filtrando){

console.log(filtrando)
}