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...
Description Javascript Mathsum() Math.sum =function() {varsum = 0;/*www.java2s.com*/for(vari = 0, j =arguments.length; i < j; i++) { sum +=arguments[i]; }returnsum; } Previous Next Related
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...
// console.log(sum); //20 // 数学对象MATH(常用) // π的值 :Math.PI // 取最大数,最小数 Math.max Math.min // let max = Math.max(2,5,35,65); // console.log(max); //65 // let min = Math.min(2,5,35,65); // console.log(min); //2 // 取整 // Math.ceil()执行...
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var sum = values.reduceRight(function(prev, cur, index, array){ return prev + cur; },10); console.log(sum); //25 这里我们可以接触一下: 获取数组最大值与最小值: var array=[1,222,32,4]; alert(Math.max.apply(null,array)); //222 ...
Math.min(1, -infinity)// -infinity 如果-infinity(无穷小)作为Math.min()的默认参数,那么每个结果都是-infinity(无穷小),这毫无用处! 然而,如果默认参数是infinity(无穷大),则无论添加任何参数返回都会是该数字 - 这就是我们想要的运行方式。 2. 为什么0.1+0.2不等于0.3 简而言之,这与JavaScript在二进制中...
map()functionbuilds a new array by changing the value of every element in an array respectively. Then the filter function is used to remove the values that do not fall in that category. Finally,thereduce()functiontakes all the values and returns a single value, which is the required sum....
varmax=arr.reduce(function(prev,cur){returnMath.max(prev,cur);}); 由于未传入初始值,所以开始时prev的值为数组第一项3,cur的值为数组第二项9,取两值最大值后继续进入下一轮回调。 forEach forEach() 方法按顺序为数组中的每个元素调用一次函数。
别人的方法一 Math方法 代码语言:javascript 复制 functionarrMaxNum2(arr){returnMath.max.apply(null,arr);}functionarrMinNum2(arr){returnMath.min.apply(null,arr);}functionarrAverageNum2(arr){varsum=eval(arr.join("+"));return~~(sum/arr.length*100)/100;} ...