"Surprising outcomes when using the splice method on an array

Question

"Surprising outcomes when using the splice method on an array

Exploring the functionalities of Array.splice().

deleteCount: A whole number indicating the quantity of old array elements to eliminate.

Understood. It seems clear. I aim to extract the final 4 items in the array. I trust that refers to elements?

arr.splice(<start>, deleteCount<how-many-to-remove>):


// {0 - 8} is a demo of object positioning
let obArr = [{0}, {1}, {2}, {3}, {4}, {5}, {6}, {7}]

// Begin from the end and eliminate four items:
obArr.splice(-1, 4)

console.log(obArr) // not the outcome as anticipated.

console.log(obArr) // expected output: [{0}, {1}, {2}, {3}]

javascript arrays

Answer 1

Answer №1

Your approach attempts to remove four values beyond the last item in the array. However, there aren't enough values after the last item to remove four. To successfully remove four values from the end of the array, you should start from an earlier index:

let myArray = [0, 1, 2, 3, 4, 5, 6, 7]

// Start from the 4th last and remove four elements:
myArray.splice(-4, 4)

console.log(myArray)

Answer 2

Your approach attempts to remove four values beyond the last item in the array. However, there aren't enough values after the last item to remove four. To successfully remove four values from the end of the array, you should start from an earlier index:

let myArray = [0, 1, 2, 3, 4, 5, 6, 7]

// Start from the 4th last and remove four elements:
myArray.splice(-4, 4)

console.log(myArray)

"Surprising outcomes when using the splice method on an array

Answer №1

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