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  • Writer's pictureJorge Guerra Pires

Removing elements from arrays in JavaScript




Removing an element: just change the first number in slice.


const colors = ["red", "green", "blue", "yellow"];
const removedElement = colors.splice(1, 1);  // Removes "green" at index 1
console.log(colors);        // Output: ["red", "blue", "yellow"]
console.log(removedElement); // Output: ["green"]



Playground here: https://playcode.io/1806994


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Here's how you can remove a single element from a JavaScript array based on its index:

1. Using the splice() method:

  • Modifies the array in place.

  • Returns an array of the removed elements.

JavaScript

const colors = ["red", "green", "blue", "yellow"];
const removedElement = colors.splice(1, 1);  // Removes "green" at index 1
console.log(colors);        // Output: ["red", "blue", "yellow"]
console.log(removedElement); // Output: ["green"]

2. Using a loop and the delete operator:

  • Doesn't modify the array's length, but leaves a hole at the removed index.

JavaScript

const numbers = [10, 20, 30, 40];
const indexToRemove = 2;

for (let i = indexToRemove; i < numbers.length - 1; i++) {
  numbers[i] = numbers[i + 1];
}
delete numbers[numbers.length - 1];

console.log(numbers); // Output: [10, 20, 40, empty]

Key points:

  • Arrays are zero-indexed.

  • splice() is generally more efficient and preferred for most cases.

  • delete technically doesn't remove elements, but creates holes with a value of undefined.

  • If you need to preserve the original array, create a copy first using methods like slice() or the spread operator (...).

Additional methods for specific cases:

  • pop() to remove the last element.

  • shift() to remove the first element.

  • filter() to create a new array without certain elements based on a condition.

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