Create aSetby applying allfnto all values ofa. Create aSetfromaand all elements inbwhose value, after applyingfndoes not match a value in the previously created set. Return the last set converted to an array. const unionBy = (a, b, fn) => { const s = new Set(a.map(v => fn(...
//设置数组的数目array.length=number//Return the length of an array 返回一个数组的长度array.length 实例 点击按钮创建数组,并显示数组元素个数。 点我 functionmyFunction() {varfruits = ["Banana", "Orange", "Apple", "Mango"];varx=document.getElementById("demo"); x.innerHTML=fruits.length; ...
Array.pop() 方法从数组中删除最后一个元素,并返回该元素的值。此方法更改数组的长度。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 var plants = ["broccoli", "cauliflower", "cabbage", "kale", "tomato"]; console.log(plants.pop()); // expected output: "tomato" console.log(plants); ...
functionappend(array,toAppend){constarrayCopy=array.slice();if(toAppend.first){arrayCopy.unshift(toAppend.first);}if(toAppend.last){arrayCopy.push(toAppend.last);}returnarrayCopy;}append([2,3,4],{first:1,last:5});// => [1, 2, 3, 4, 5]append(['Hello'], { last: 'World' })...
return -1; }else if(a>b){ return 1; }else{ return 0; } } 用上面的比较函数对数字进行排序,可以得到我们想要的结果 console.log(arr.sort(compare)); // [1, 3, 5, 14, 25]; 当然这个方法还能简化; console.log(arr.sort(function(a,b){return a-b})); ...
varmyArray=['Dashes','are','awesome','!'];console.log(myArray.join('-').split('-')); As you can see, we’re justjoining it with dashesand thensplitting it up again, making itreturn the original array! array.reverse() it reverses an array!Here’s an example: ...
sort() Return Value Returns the array after sorting the elements of the array in place (meaning that it changes the original array and no copy is made). Example 1: Sorting the Elements of an Array WhencompareFunctionis not passed,
Array.from() Array.from() is a static property of the JavaScript Array object. You can only use it as Array.from(). Using x.from(), where x is an array will return undefined. Syntax Array.from(object, mapFunction, thisValue)
Here,arris an array. map() Parameters Themap()method takes in: callback- The function called for every array element. Its return values are added to the new array. It takes in: currentValue- The current element being passed from the array. ...
fn.button.noConflict() // return $.fn.button to previously assigned value $.fn.bootstrapBtn = bootstrapButton // give $().bootstrapBtn the Bootstrap functionality Events Bootstrap provides custom events for most plugins' unique actions. Generally, these come in an infinitive and past ...