When working with arrays in JavaScript, one common task is calculating the sum of all the numbers contained within that array. Whether you’re developing a web application, analyzing data, or just experimenting with code, knowing how to efficiently sum an array can save you time and effort. ...
In javascript, we can calculate the sum of the elements of the array by using the Array.prototype.reduce() method. The reduced method for arrays in javascript helps us specify a function called reducer function that gets called for each of the elements of an array for which we are calling ...
const sum = [0, 1, 2, 3, 4].reduce((acc, curr) => acc + curr) const sum1 = [0, 1, 2, 3, 4].reduceRight((acc, curr) => acc + curr) console.log(sum) // 10 console.log(sum1) // 10 总结 至此我们已经将数组中所有的属性和方法都总结了一遍,并且给出了最基本的用法示例。
function arraySum(arr) { var sum = 0; if (Object.prototype.toString.call(arr) === '[object Array]') { for (var i = 0; i < arr.length; i++) { if (typeof arr[i] === "number" && !isNaN(arr[i])) { sum += arr[i]; } else { va...
现在,我们就可以使用forEach卖弄一个稍显完整的例子了,数组求和:var sum = 0; [1, 2, 3, 4].forEach(function (item, index, array) { console.log(array[index] == item); // true sum += item; }); alert(sum); // 10再下面,更进一步,forEach除了接受一个必须的回调函数参数,还可以接受一...
log(sum); array.every( fn ) : 检测数值元素的每个元素是否都符合条件。布尔值。如果所有元素都通过检测返回 true,否则返回 false。原始值不变。 不会对空数组进行检测。 如果数组中检测到有一个元素不满足,则整个表达式返回 false ,且剩余的元素不会再进行检测。如果所有元素都满足条件,则返回 true。 fn( ...
let sum = arr.reduce((pre, cur, index, array) => { return pre + cur }) console.log(sum) // 15 1. 2. 3. 4. 5. a[n] = 1 通过长度控制 数组的length(长度)并不是只读属性,可以通过更改长度值更改数组项。 let a = [1, 2, 3, 4] ...
Array.prototype.sum=function(){returnthis.reduce(function(partial,value){returnpartial+value},0)};[3,4,5,6,10].sum()// <- 28 9.slice() slice()方法用于提取目标数组的一部分,返回一个新数组,原数组不变。 arr.slice(start,end) 它的第一个参数为起始位置(从0开始,会包括在返回的新数组之中...
Array.prototype.sum =function(){returnthis.reduce(function(partial, value){returnpartial + value},0)}; [3,4,5,6,10].sum()// <- 28 9.slice() slice()方法用于提取目标片段的一部分,返回一个新副本,原先的位置不变。 arr.slice(start,end) ...
In this article we will see how to find a pair of items in an array which has sum equals to a specific target number. So we will use JavaScript to implement the algorithm. Understanding the Problem The problem at hand is to find the pair of numbers in the array whose sum is equal...