Before the introduction of the reduce() method, we used to calculate the sum of array elements using the for a loop. We would iterate the loop from 0 to the length of the array as indexing of the array starts from 0 and then calculate the sum inside the for a loop. Let us consider...
var i = array.length; while (i--) { sum += parseInt(array[i]); } return sum; } console.time("getSum"); for (var i = 0; i < 1000000; i++) { var sum = 0; getSum(arr); } console.timeEnd("getSum"); // getSum: 7690.056ms console.log("使用while循环:sum=" + sum);...
array.push(item1, item2, ..., itemX) 例 varnumbers = [65, 44, 12, 4];functiongetSum(total, num) {returntotal +num; }functionmyFunction(item) { console.log(numbers.reduce(getSum)); } 结果:125 2.18 reduce() 定义和用法 reduce() 方法接收一个函数作为累加器,数组中的每个值(从左到...
const url = document.getElementById('queryURL').value;const sampleIndex = document.getElementById( ***1***'whichSampleInput').valueAsNumber; ***1***const myData = tf.data.csv(url); ***2***const sample = await myData.skip(sampleIndex) ***3***.take(1) ***4***.toArray();...
map()是array的一个方法 作用: 对array中每一个元素调用自定义函数 'use strict';functionpow(x){returnx*x; }vararr=[1,2,3,4,5]varnewarray=arr.map(pow) map的回调函数有三个参数: callback(currentValue, index, array)通常只要第一个参数 ...
This post will discuss how to calculate the sum of all array elements in JavaScript. There are several ways to get the sum of all elements of an array in JavaScript, depending on the performance, readability, and compatibility of the code. Here are some of the functions that we can use,...
This tutorial teaches how to get the sum of an array of numbers in JavaScript. Explore various methods, including for loops, reduce, and forEach. Learn to sum arrays effectively and improve your coding skills with practical examples and clear explanation
function sumofArray(sum, num) { return sum + num; } function myGeeks(item) { document.getElementById("GFG").innerHTML = arr.reduce(sumofArray); } 输出: 在单击按钮之前: 单击按钮后: 范例2:本示例使用reduce()方法返回所有数组元素的舍入和。 <!DOCTYPE html> JavaScript...
Array ( 数组)类型 Date (日期) 代码语言:javascript 代码运行次数:0 运行 AI代码解释 vard=newDate();//1) 获得当前年份 d.getYear()//2) 获得年份的全称 d.getFullYear()//3) 获得月份 d.getMonth()//4) 获得日期 d.getDate()//5) 获得星期 d.getDay()//6) 获得时间 d.getHours()//7)...
并且 js functionfunc(a=55){console.log(arguments[0]);}func();// undefined 规范 Specification ECMAScript® 2026 Language Specification #sec-arguments-exotic-objects 浏览器兼容性 参见 Function