javascript - 如何找到数字数组的总和(How to find the sum of an array of numbers)

Question

Given an array [1, 2, 3, 4] , how can I find the sum of its elements?

(给定一个数组[1, 2, 3, 4] ，我如何找到它的元素之和？)

(In this case, the sum would be 10 .)

(（在这种情况下，总和为10 ）)

I thought $.each might be useful, but I'm not sure how to implement it.

(我认为$.each可能有用，但是我不确定如何实现它。)

  ask by akano1 translate from so

Answer 1

In Lisp , this'd be exactly the job for reduce .

(在Lisp中 ，这正是reduce工作量的工作。)

You'd see this kind of code:

(您会看到以下代码：)

(reduce #'+ '(1 2 3)) ; 6

Fortunately, in JavaScript, we also have reduce !

(幸运的是，在JavaScript中，我们也有reduce ！)

Unfortunately, + is an operator, not a function.

(不幸的是， +是运算符，而不是函数。)

But we can make it pretty!

(但是我们可以使其漂亮！)

Here, look:

(在这里，看看：)

const sum = [1, 2, 3].reduce(add,0); // with initial value to avoid when the array is empty

function add(accumulator, a) {
    return accumulator + a;
}

console.log(sum); // 6

Isn't that pretty?

(那不是很漂亮吗？)

:-)

(:-))

Even better!

(更好！)

If you're using ECMAScript 2015 (aka ECMAScript 6 ), it can be this pretty:

(如果您使用的是ECMAScript 2015（又名ECMAScript 6 ），它可能会很漂亮：)

const sum = [1, 2, 3].reduce((partial_sum, a) => partial_sum + a,0); 
console.log(sum); // 6