Can a for loop iterate through a conditional statement using the length property?

Question

Can a for loop iterate through a conditional statement using the length property?

Glad you're here to check this out. See the code below.


let questions = [];

let Question = function(question, answers, number) {
    this.question = question;
    this.answers = answers;
    this.number = number;
}

let question1 = new Question('Is JavaScript the best programming language?', 
['No', 'Yes'], 1);

let question2 = new Question('Is JavaScript a web development language?', 
['No', 'Yes'], 1);

let question3 = new Question(`What is JavaScript's official server side 
application called?`, ['BootStrap', 'Python', 'Node.js'], 2);

questions = [question1, question2, question3];

Question.randomQuestion = function() {
    let randomNum = Math.floor(Math.random() * 3);
    let randomQuestion = questions[randomNum];

    return randomQuestion;
}

Question.display = function(randomQuestion) {
    console.log(randomQuestion.question);
    debugger;
        // Why does the conditional give me undefined?
        for (let i = 0; i < questions[i].answers[i].length; i++)
        console.log(`${randomQuestion.answers[i]}`);    
    }

I'm trying to find the answers property length in each iteration, but I keep getting an error that says answers is undefined. Any idea why this is happening and a better way to achieve this?

javascript arrays object for-loop iteration

Answer 1

Answer №1

There seems to be a couple of errors in the code. When iterating through two arrays, it's necessary to use two loops. I've included a snippet of code below that I believe will be helpful :

let questions = [];

let Question = function (question, answers, number) {
	this.question = question;
	this.answers = answers;
	this.number = number;
}

let question1 = new Question('Is Python the best programming language?',
	['No', 'Yes'], 1);

let question2 = new Question('Is Python a web development language?',
	['No', 'Yes'], 1);

let question3 = new Question(`What is Python's official server side 
application called?`, ['Django', 'Flask', 'Node.js'], 2);

questions = [question1, question2, question3];

const randomQuestion = function () {
	let randomNum = Math.floor(Math.random() * 3);
	let randomQuestion = questions[randomNum];
	return randomQuestion;
}

const display = function (randomQuestion) {
	const random_question = randomQuestion();
	console.log(random_question.question);
	//debugger;
	// Why am I getting undefined for the conditional?
	// Display all questions and answers
	for (let i = 0; i < questions.length; i++)
		for (let j = 0; j < questions[i].answers.length; j++)
			console.log(`${questions[i].answers[j]}`);
	// Alternatively :
	questions.forEach(e => {
		console.log(e.question);
		e.answers.forEach(a => {
			console.log(a)
		})
	})
}

display(randomQuestion);

Answer 2

There seems to be a couple of errors in the code. When iterating through two arrays, it's necessary to use two loops. I've included a snippet of code below that I believe will be helpful :

let questions = [];

let Question = function (question, answers, number) {
	this.question = question;
	this.answers = answers;
	this.number = number;
}

let question1 = new Question('Is Python the best programming language?',
	['No', 'Yes'], 1);

let question2 = new Question('Is Python a web development language?',
	['No', 'Yes'], 1);

let question3 = new Question(`What is Python's official server side 
application called?`, ['Django', 'Flask', 'Node.js'], 2);

questions = [question1, question2, question3];

const randomQuestion = function () {
	let randomNum = Math.floor(Math.random() * 3);
	let randomQuestion = questions[randomNum];
	return randomQuestion;
}

const display = function (randomQuestion) {
	const random_question = randomQuestion();
	console.log(random_question.question);
	//debugger;
	// Why am I getting undefined for the conditional?
	// Display all questions and answers
	for (let i = 0; i < questions.length; i++)
		for (let j = 0; j < questions[i].answers.length; j++)
			console.log(`${questions[i].answers[j]}`);
	// Alternatively :
	questions.forEach(e => {
		console.log(e.question);
		e.answers.forEach(a => {
			console.log(a)
		})
	})
}

display(randomQuestion);

Can a for loop iterate through a conditional statement using the length property?

Answer №1

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