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I am trying to write a function which reverses the elements of an array without defining a new empty array in the function.

let arrayValue = [1, 2, 3, 4, 5]

function remove(array, index) {
return array.slice(0, index).concat(array.slice(index + 1));

function reverseArrayInPlace(array) {
  for (i = array.length - 2; i >= 0; i--) {
    let removedCharacter = array[i];
    array = array.concat(removedCharacter);
    array = remove(array, i);
    return array;

When I console.log(reverseArrayInPlace(arrayValue)) I am getting the reverse order of [5, 4, 3, 2, 1].

However when I try to just do reverseArrayInPlace(arrayValue) and then console.log(arrayValue), I am getting [1, 2, 3, 4, 5] which is the value defined at the beginning.

Is there a way of updating the arrayValue binding in the function and then when it is console.log outside the function, it is showing the reversed order?

// show cases of even and odd lengths
const x = [1,2,3,4];
const y = [1,2,3,4,5];

for (let i = 0; i < x.length / 2; i++) {
  const tmp = x[i];

  x[i] = x[x.length - 1 - i];
  x[x.length - 1 - i] = tmp;

for (let i = 0; i < y.length / 2; i++) {
  const tmp = y[i];

  y[i] = y[y.length - 1 - i];
  y[y.length - 1 - i] = tmp;

// [4, 3, 2, 1]

// [5, 4, 3, 2, 1]

How can I reverse an array in JavaScript without using libraries , If that's the case, you can implement your own version of .reverse() function reverseArr(input) { var ret = new Array; for(var i = input.length-1; i >= 0; i--)� However, we don’t create a new array like the above method. Instead, we reverse the original array itself. In this method we swap the elements of the array. The first element is swapped with the last element. The second element id swapped with the last but one element and so on. For instance, consider array [1, 2, 3, …., n-2, n-1, n].

The MDN docs for Array's slice and concat methods explain that these methods return new arrays, rather than modifying the existing arrays. If you are looking for a built-in Array method for modifying arrays, splice will do the job. However, it's going to be more complicated to implement this using splice than to just use a for loop as the other answers suggest.

How to Reverse Arrays in JavaScript Without Using .reverse(), Write two functions reverseArray and reverseArrayInPlace. The first For the reverseArray function, if we're going to produce a new array we need an empty array to fill up later: But if our length is 8, as it is in array2 , then the loop will stop at index 4, which is actually 1 index past where we want to stop. This is the dynamic solution for reversing the array of any datatype.Some of the key points in my algorithm is first calculate the half of array length and add check to stop iteration when array indexes have same value.The stage having same indexes depict that it start the reverse operation again.So at this stage break the outer loop by using

You could just swap values symmetrically around the midpoint of the array, like

const arr = [0,1,2,3,4];
const len = arr.length;
for(let i = 0; i < len/2; i++){
  let temp = arr[i];
  arr[i] = arr[len-1-i];
  arr[len-1-i] = temp;

Creating and Using Arrays, that creates the array, puts some values in it, and displays the values. declare an array of integers anArray = new int[10]; // create an array of integers // assign An array's type is written type[] , where type is the data type of the elements the declaration for an array variable does not create an array and does not allocate� C Program to Reverse an Array - This program reverses the array elements. For example if a is an array of integers with three elements such that a = 1 a = 2 a = 3 Then on reversing the

function reverseArrayInPlace(array) {
 for (let i = 0; i < array.length / 2; i++) {
  const oppositeArrayIndex = array.length - (i + 1);
  const oppasiteArrayValue = array[oppositeArrayIndex];
  array[oppositeArrayIndex] = array[i];
  array[i] = oppasiteArrayValue;

JavaScript Arrays - tips, tricks and examples, In Javascript, there are only 6 data types defined – the primitives (boolean, number You can use any name as property for an objects, including numbers or even empty string. So ['John'] is identical to new Array('John') but [10] it's not the same thing to You can add your own custom method: new_array = arr. reverse(). printf(" Please Enter the size of an array: "); scanf("%d",&Size); The below For loop in reverse array program will help to iterate each cell present in a[5] array. For loop iteration will start at 0, and the condition inside the for loops (i < Size) will ensure the compiler, not to exceed the array limit.

Arrays, It is not convenient to use an object here, because it provides no methods to There are two syntaxes for creating an empty array: So new elements are added or taken always from the “end”. Arrays have their own implementation of toString method that returns a Write the function sumInput() that:. After a call to this method, the element at myArray [i], where i is any index in the array, moves to myArray [j], where j equals (myArray.Length + myArray.GetLowerBound (0)) - (i - myArray.GetLowerBound (0)) - 1. The Reverse method can be used to reverse a jagged array. This method is an O (n) operation, where n is length.

Array.prototype.reverse(), The reverse() method reverses an array in place. The first array element becomes the last, and the last array element becomes the first. Objects which do not contain a length property reflecting the last in a series of consecutive, zero -based The definition of 'Array.prototype.reverse' in that specification. foreach (var value in array.OrderBy(a => a)) Console.WriteLine(value); Now, before you hover over the answer below to find out how to do it in reverse, use intellisense in Visual Studio, or google LINQ descending order and determine what method you would replace OrderBy with, to write out the array in descending order: Answer

5. Working with Arrays and Loops, For instance, you can define an array literal and assign it to a variable: directly, using square brackets containing their index (position in the array). You can't use the empty comma, though, to add an undefined array element to the end the elements, and then use the reverse method to reverse the array member order: The array is passed to the function, and a new array is created, and contents of the passed array (in reverse order) are copied into it, and finally, contents of the new array are copied into the array passed to the function.

  • Your remove function isn't in-place at all. An in-place solution would not reassign the array variable, and it would not need to return a value. An in-place solution would actually mutate the passed-in array by swapping its elements with each other. Please try that and show us your attempt. Think non-functional.
  • The solution for this exercise had the return statement at the end so I was assuming that my function had to return something as well. Thank you for the clarification on in-place.
  • This was the answer that I gave 30 minutes ago
  • I disagree, this code is more self-documenting thanks to variable naming than the one from the other answer, that you didn't mark as "low quality"
  • its just suggestion. generally code only answers will go to low quality queues by SO(its not me who will mark as low or high quality). it came to my review thats why suggested. hope you understood now.Thanks