创建累积和在JavaScript数组 [英] Creating an array of cumulative sum in javascript

问题描述

这是什么，我需要做的一个例子：

This is an example of what I need to do:

var myarray = [5, 10, 3, 2];

var result1 = myarray[0];
var result2 = myarray[1] + myarray[0];
var result3 = myarray[2] + myarray[1] + myarray[0];
var result4 = myarray[3] + myarray[2] + myarray[1] + myarray[0];

让所有将输出5，15，18，20

so all that would output 5, 15, 18, 20

但不是写出像所有的增值经销商，我希望它这样说：

but instead of writing out all the vars like that, I want it to say something like:

var result = arrayitem + the sum of any previous items 

这是否有意义？那可能吗？我怎么做？

Does that make sense? Is that possible? How do I do that?

推荐答案

JavaScript的减少提供当前指数，这是在这里有用：

Javascript's reduce provides the current index, which is useful here:

var myarray = [5, 10, 3, 2];
var new_array = [];
myarray.reduce(function(a,b,i) { return new_array[i] = a+b; },0);
new_array // [5, 15, 18, 20]

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