for Loop

Array iteration is a crucial concept when working with arrays. It allows us to process each element in an array, perform operations, and make decisions based on their values. In this chapter, we will explore for loop for iterating over arrays.

Syntax

The for loop is a fundamental tool for iterating over an array element by element. It allows us to access each element in the array by element index. The syntax for a for loop is as follows:

In this syntax:

let i = 0 initializes a loop counter variable i to zero;
i < array.length defines the condition for the loop to continue. It will run as long as i is less than the length of the array;
i += 1 increments the loop counter after each iteration.

Example

Here's an example of using the for loop to access and display the elements of the students array:


              12345
            
const students = ["Brandon", "Mario", "Saul"];

for (let i = 0; i < students.length; i += 1) {
  console.log(students[i]);
}

Line 1: This line declares an array called students and initializes it with three strings, which represent the students' names. The array contains "Brandon", "Mario", and "Saul";
Line 3: This line starts a for loop. It has three parts separated by semicolons:
- let i = 0;: This part initializes a variable i and sets it to 0. i is used as a loop counter;
- i < students.length;: This part is the condition for the loop to continue. The loop will continue as long as i is less than the length of the students array;
- i += 1: This part is the update statement, which increments the value of i by 1 after each iteration.
Line 4: Inside the for loop, this line uses the console.log() function to log the value at the i-th index of the students array. In the first iteration, i is 0, so it logs the name at index 0, which is "Brandon". In the second iteration, it logs "Mario", and in the third iteration, it logs "Saul".

1. What is the purpose of a `for` loop when working with arrays?

2. What should be the condition for the loop to iterate through the entire `computers` array?

3. What should be the condition for the loop to iterate through the `computers` array to show only the first two elements?

Все було зрозуміло?

Дякуємо за ваш відгук!

Секція 4. Розділ 5