Arrange the array so that the item is placed at the beginning while maintaining the original order

Question

Arrange the array so that the item is placed at the beginning while maintaining the original order

Currently facing a roadblock with this particular issue. I am attempting to create a function that accepts an index as input and rearranges the element at that index in an array to be placed at the beginning, while keeping the order of the other elements accurate.

const unorderedArr = [item1, item2, item3, item4]
const reorderArr = (i, arr) => { 
 ...
}

const reorderedArr = reorderArr(2, unorderedArr)
// [item3, item4, item1, item2]

Open to any hints!

javascript arrays

Answer 1

Answer №1

To achieve the desired result, you can implement a swapping technique with the preceding element until the index reaches zero.

const
    switchElements = (array, i) => {
        while (i) {
            [array[i], array[i - 1]] = [array[i - 1], array[i]];
            i--;
        }
        return array;
    };

console.log(...switchElements(['item1', 'item2', 'item3', 'item4'], 2));

Answer 2

To achieve the desired result, you can implement a swapping technique with the preceding element until the index reaches zero.

const
    switchElements = (array, i) => {
        while (i) {
            [array[i], array[i - 1]] = [array[i - 1], array[i]];
            i--;
        }
        return array;
    };

console.log(...switchElements(['item1', 'item2', 'item3', 'item4'], 2));

Answer 3

Answer №2

Here is a simple way to achieve this:

const unorderedArr = ["item1", "item2", "item3", "item4"];
const reorderArr = (i, arr) => {
  const movingElement = arr[i]; // get the element at index i
  arr.splice(i, 1); // remove the element from index i next to one ( item 3)
  arr.unshift(movingElement); // add the element to the beginning of the array
  return arr;
};

const reorderedArr = reorderArr(2, unorderedArr);
console.log("reorderedArr", reorderedArr);
//  [ 'item3', 'item1', 'item2', 'item4' ]

Answer 4

Here is a simple way to achieve this:

const unorderedArr = ["item1", "item2", "item3", "item4"];
const reorderArr = (i, arr) => {
  const movingElement = arr[i]; // get the element at index i
  arr.splice(i, 1); // remove the element from index i next to one ( item 3)
  arr.unshift(movingElement); // add the element to the beginning of the array
  return arr;
};

const reorderedArr = reorderArr(2, unorderedArr);
console.log("reorderedArr", reorderedArr);
//  [ 'item3', 'item1', 'item2', 'item4' ]

Answer 5

Answer №3

slice(i) function will retrieve an array starting from the specified index (inclusive), while slice(0, i) will extract an array from the beginning to the index specified (excluding). The resulting array will be:

["item3","item4","item1","item2"]

const unorderedArr = ['item1', 'item2', 'item3', 'item4']
const reorderArr = (i, arr) => { 
  return [...arr.slice(i), ...arr.slice(0,i)];
}

const reorderedArr = reorderArr(2, unorderedArr);
console.log(reorderedArr)

Answer 6

slice(i) function will retrieve an array starting from the specified index (inclusive), while slice(0, i) will extract an array from the beginning to the index specified (excluding). The resulting array will be:

["item3","item4","item1","item2"]

const unorderedArr = ['item1', 'item2', 'item3', 'item4']
const reorderArr = (i, arr) => { 
  return [...arr.slice(i), ...arr.slice(0,i)];
}

const reorderedArr = reorderArr(2, unorderedArr);
console.log(reorderedArr)

Arrange the array so that the item is placed at the beginning while maintaining the original order

Answer №1

Answer №2

Answer №3

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