Are you wondering how to get the last element of an array in JavaScript? JavaScript has a lot of built-in methods that can be used to manipulate arrays. Let’s find out what we can implement to access the last element of the array. Using length property Suppose, you have an array an...
varmyArray=[1,2,3,4,5,6];// Fastest method, requires the array is in a variablemyArray[myArray.length-1];// Also very fast but it will remove the element from the array also, this may or may not matter in your case.myArray.pop();// Slowest but very readable and doesn't req...
Now, let’s explore multiple ways to retrieve the last element of an array in JavaScript: #Using Array Index without Mutating the Original Array The last element can be obtained using array indexing without modifying the original array. The array always starts with zero indexes and the last ele...
Reverse the array first, then check whether the value was found or not, then subtract the reversed index from the array's last index to get the correct answer. var arr = [{name:"Steve",toppedIn:"Biology"},{name:"Carol",toppedIn:"Maths"},{name:"Steve",toppedIn:"Chemistry"}]; cons...
length 因为数组索引是从0开始,所以我们可以通过访问数组长度减去1,这样就达到了访问最后一个元素的目的。...var my_array = [1,2,3,4,5]; var last_element = my_array[my_array.length - 1]; // 5 prototype属性我们可以将访问数组最后一个元素绑定到原型链上...Array.prototype.last = function(){...
If such an element is found, * findLastIndex immediately returns that element index. Otherwise, findLastIndex returns -1. */ export function findLastIndex<T>(array: Array<T>, predicate: (value: T, index: number, obj: T[]) => boolean): number { let l = array.length; while (l--...
letarr=[1,2,3];letlastElement=arr.pop();// lastElement 为 3,arr 变为 [1, 2] 2.2.2 使用shift方法 shift方法可以删除数组开头的元素,并返回该元素。 letarr=[1,2,3];letfirstElement=arr.shift();// firstElement 为 1,arr 变为 [2, 3] ...
functiongetPrimes(arr){returnarr.filter(function(element){if(element===1)returnfalse;if(element===2)returntrue;for(vari=2; i<element; i++){if(element%i===0){returnfalse; } }returntrue; }); } Array.prototype.map() functionpow(x){returnx*x; ...
arrayA.push(5); console.log(copyA.arrayA); // [1, 2, 3, 4] Element.matches 精确匹配document.getElementById('list').addEventListener('click', function (e) { // 兼容性处理 var event = e || window.event; var target = event.target || event.srcElement; if (target.matches('li....
您可以使用已移至Stage 4 in Aug, 2021的Array.at()方法