Remove the Last Element from an Array

medium

Last Updated - 31/08/2024

Problem Statement Solution 1: Using slice() Method Solution 2: Using filter() Method Solution 3: Using Array.from() Method Solution 4: Using map() and slice() Solution 5: Using reduce() Method Solution 6: Using for Loop Solution 7: Using for...of Loop Solution 8: Using splice() Method Solution 9: Using concat() and slice() Solution 10: Using Destructuring Assignment More Problems Solutions

Problem Statement

Write a function that takes an array as input and returns a new array with the last element removed. The original array should not be modified. Your solution should return a new array that contains all the elements of the input array except for the last one.

Example 1

Input: array = [1, 2, 3, 4, 5]

Output: [1, 2, 3, 4]

Solution 1: Using slice() Method

function removeLastElementWithSlice(arr) {
  return arr.slice(0, -1);
} 

const array1 = [1, 2, 3, 4, 5];
removeLastElementWithSlice(array1);  //output: [1, 2, 3, 4]

Solution 2: Using filter() Method

function removeLastElementWithFilter(arr) {
  return arr.filter((_, index) => index < arr.length - 1);
} 

const array1 = [1, 2, 3, 4, 5];
removeLastElementWithFilter(array1);  //output: [1, 2, 3, 4]

Solution 3: Using Array.from() Method

function removeLastElementWithArrayFrom(arr) {
  return Array.from(arr).slice(0, -1);
} 

const array1 = [1, 2, 3, 4, 5];
removeLastElementWithArrayFrom(array1);  //output: [1, 2, 3, 4]

Solution 4: Using map() and slice()

function removeLastElementWithMap(arr) {
  return arr.map((item, index) => (index < arr.length - 1 ? item : null)).filter(item => item !== null);
} 

const array1 = [1, 2, 3, 4, 5];
removeLastElementWithMap(array1);  //output: [1, 2, 3, 4]

Solution 5: Using reduce() Method

function removeLastElementWithReduce(arr) {
  return arr.reduce((acc, item, index) => {
    if (index < arr.length - 1) acc.push(item);
    return acc;
  }, []);
} 

const array1 = [1, 2, 3, 4, 5];
removeLastElementWithReduce(array1);  //output: [1, 2, 3, 4]

Solution 6: Using for Loop

function removeLastElementWithForLoop(arr) {
  let newArray = [];
  for (let i = 0; i < arr.length - 1; i++) {
    newArray.push(arr[i]);
  }
  return newArray;
} 

const array1 = [1, 2, 3, 4, 5];
removeLastElementWithForLoop(array1);  //output: [1, 2, 3, 4]

Solution 7: Using for...of Loop

function removeLastElementWithForOf(arr) {
  let newArray = [];
  let index = 0;
  for (const item of arr) {
    if (index < arr.length - 1) {
      newArray.push(item);
    }
    index++;
  }
  return newArray;
} 

const array1 = [1, 2, 3, 4, 5];
removeLastElementWithForOf(array1);  //output: [1, 2, 3, 4]

Solution 8: Using splice() Method

function removeLastElementWithSplice(arr) {
  return arr.slice(0, -1);
} 

const array1 = [1, 2, 3, 4, 5];
removeLastElementWithSplice(array1);  //output: [1, 2, 3, 4]

Solution 9: Using concat() and slice()

function removeLastElementWithConcat(arr) {
  return [].concat(arr.slice(0, -1));
} 

const array1 = [1, 2, 3, 4, 5];
removeLastElementWithConcat(array1);  //output: [1, 2, 3, 4]

Solution 10: Using Destructuring Assignment

function removeLastElementWithDestructuring(arr) {
  const [ ...newArray ] = arr;
  newArray.pop(); // Removes the last element
  return newArray;
} 

const array1 = [1, 2, 3, 4, 5];
removeLastElementWithDestructuring(array1);  //output: [1, 2, 3, 4]