JavaScript For Loop

Key Points:

• The for loop is a control flow statement for executing code repeatedly in JavaScript.
• It is designed for iterating over arrays or sequences of numbers.
• Syntax:

for (initialization; condition; increment/decrement) {
  // Code to be executed in each iteration
}

• Initialization: Executes once at the start to initialize a counter variable.
• Condition: Evaluated before each iteration. Loop continues if true; otherwise, it exits.
• Increment/Decrement: Executed after each iteration, often used to update the counter.
• Versatile loop for iterating over arrays or iterable objects.
• The break statement exits the loop prematurely.
• The continue statement skips the rest of the code for the current iteration.

Examples:

Basic Numeric Iteration:

for (let i = 0; i < 5; i++) {
  console.log(i);
}

This loop prints numbers from 0 to 4.

Iterating Over an Array:

const fruits = ['apple', 'banana', 'orange'];

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

This loop iterates through each element in the fruits array.

Skipping Even Numbers:

for (let i = 0; i < 10; i++) {
  if (i % 2 === 0) {
    continue; // Skip even numbers
  }

This loop prints odd numbers from 0 to 9, skipping even numbers

Breaking the Loop Early:

for (let i = 0; i < 10; i++) {
  if (i === 5) {
    break; // Exit the loop when i reaches 5
  }
  console.log(i);
}

This loop prints numbers from 0 to 4 and exits when i becomes 5.

Nested Loop for Matrix Iteration:

const matrix = [
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9]
];

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

This nested loop iterates through each element in a 2D matrix.

These examples demonstrate the versatility of the for loop in various scenarios, including basic numeric iteration, array traversal, skipping specific values, and breaking out of the loop early.