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JavaScript Array Methods

JavaScript provides a variety of array methods that allow you to manipulate and interact with arrays in different ways. Below is a brief overview of some common array methods, including `push`, `pop`, `shift`, `unshift`, `splice`, `slice`, `forEach`, `map`, `filter`, and `reduce`.

  1. `push()`: Adds one or more elements to the end of an array and returns the new length of the array.
const animals = ['cat', 'dog'];
animals.push('elephant', 'giraffe');
console.log(animals); // Output: ['cat', 'dog', 'elephant', 'giraffe']

In this example, the `push()` method adds 'elephant' and 'giraffe' to the end of the `animals` array.

  1. `pop()`: Removes the last element from an array and returns the removed element.
const animals = ['cat', 'dog', 'elephant'];
const lastAnimal = animals.pop();
console.log(lastAnimal); // Output: 'elephant'
console.log(animals); // Output: ['cat', 'dog']

Here, the `pop()` method removes the last element ('elephant') from the `animals` array and returns it.

  1. `shift()`: Removes the first element from an array and returns the removed element.
const animals = ['cat', 'dog', 'elephant'];
const firstAnimal = animals.shift();
console.log(firstAnimal); // Output: 'cat'
console.log(animals); // Output: ['dog', 'elephant']

In this example, the `shift()` method removes the first element ('cat') from the `animals` array and returns it.

  1. `unshift()`: Adds one or more elements to the beginning of an array and returns the new length of the array.
const animals = ['cat', 'dog'];
animals.unshift('elephant', 'giraffe');
console.log(animals); // Output: ['elephant', 'giraffe', 'cat', 'dog']

Here, the `unshift()` method adds 'elephant' and 'giraffe' to the beginning of the `animals` array.

  1. `splice()`: Adds and/or removes elements from an array. The first argument is the start index, the second argument is the number of elements to remove, and the remaining arguments are the elements to add.
const animals = ['cat', 'dog', 'elephant'];
animals.splice(1, 1, 'giraffe'); // Remove 1 element at index 1 and insert 'giraffe'
console.log(animals); // Output: ['cat', 'giraffe', 'elephant']

In this example, the `splice()` method removes one element at index 1 ('dog') and inserts 'giraffe' in its place.

  1. `slice()`: Returns a shallow copy of a portion of an array. The first argument is the start index, and the second argument is the end index (non-inclusive).
const animals = ['cat', 'dog', 'elephant', 'giraffe'];
const slicedAnimals = animals.slice(1, 3);
console.log(slicedAnimals); // Output: ['dog', 'elephant']

Here, the `slice()` method creates a new array containing elements from index 1 to index 3 (non-inclusive) of the `animals` array.

  1. `forEach()`: Executes a provided function once for each array element. It doesn't return a new array or modify the existing one.
const numbers = [1, 2, 3];
numbers.forEach((number) => console.log(number * 2));
// Output: 2, 4, 6

In this example, the `forEach()` method calls the provided function for each element.

  1. `map()`: Creates a new array with the results of calling a provided function on every element in the array. The original array remains unchanged.

const numbers = [1, 2, 3];
const doubledNumbers = numbers.map((number) => number * 2);
console.log(doubledNumbers); // Output: [2, 4, 6]

In this example, the `map()` method creates a new array containing the results of multiplying each element in the `numbers` array by 2.

  1. `filter()`: Creates a new array with all elements that pass the test implemented by the provided function.
const numbers = [1, 2, 3, 4, 5];
const evenNumbers = numbers.filter((number) => number % 2 === 0);
console.log(evenNumbers); // Output: [2, 4]

Here, the `filter()` method creates a new array containing only the even elements from the `numbers` array.

  1. `reduce()`: Applies a function against an accumulator and each element in the array (from left to right) to reduce it to a single value.
const numbers = [1, 2, 3, 4, 5];
const sum = numbers.reduce((accumulator, currentValue) => accumulator + currentValue, 0);
console.log(sum); // Output: 15

In this example, the `reduce()` method calculates the sum of all elements in the `numbers` array. The accumulator is initialized with a value of 0, and the provided function adds each element to the accumulator in turn.

These are some of the most commonly used JavaScript array methods that allow you to manipulate and interact with arrays effectively. Each method has its unique functionality, making it easier to perform various operations on arrays.

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