添加数组的总和.显示一个输出 [英] Add sums of array. Display one output

问题描述

更新:以下是该问题的答案.感谢在另一个线程上进行dougtesting. 将数组加在一起，显示总和

Update: The answer to this question is bellow. Thanks to dougtesting on a different thread. add array together, display sum

function hello() {
    var arr = [];

    for (var i = 0; i < 10; i++) {
        arr.push(prompt('Enter number' + (i+1)));
    }

    var total = 0;

    for(i=0; i<arr.length; i++) {
        var number = parseInt(arr[i], 10);
        total += number;
    }

    console.log(total);
}

//答案结束.

我正在尝试让用户输入10个数字.然后将这些数字加在一起并向用户显示输出.我能够将输入量(10)放入数组，但无法获取数组内容.我觉得我缺少一些简单的东西.您介意看看吗?

I am trying to have a user input 10 numbers. Then add those numbers together and display the output to the user. I was able to get the amount of inputs (10) into a array but I can't get arrays contents. I feel like I'm missing something simple. Would you mind taking a look?

// https://stackoverflow.com/questions/28252888/javascript-how-to-save-prompt-input-into-array
var arr = [];                               // define our array

for (var i = 0; i < 10; i++) {              // loop 10 times
  arr.push(prompt('Enter number' + (i+1))); // push the value into the array
}

alert('Full array: ' + arr.join(', '));    // alert the result

var arrEquals = []; //Empty Arr
 arrEquals = arr.push(); //turn string into var

alert (arrEquals);//show string to admin for debug

//(for loop) console out # of  array elements. does not output what is in array
//this is half the battle  
    for (var a = 0; a < arrEquals; a++){
         var a = Number(a); //ensure input is Number()
           console.log(a + "A"); //used for debug
    }


//taks sums in array and adds them together
//this is the other half of the problem
// https://www.w3schools.com/jsref/jsref_forEach.asp   
// var sum = 0;
// var numbers = [65, 44, 12, 4];

// function myFunction(item) {
//     sum += item;
//     demo.innerHTML = sum;
// }

推荐答案

这可能是Javascript内置在数组

This is probably one of the simplest examples of something that Javascript's built in array .reduce() function would be used for. Effectively, you're "reducing an array to a single value".

通过获取数组并在每个项目上运行一个函数来减少工作量.该回调"函数接收前一个函数返回的值，以某种方式对其进行处理，然后返回一个新值.值得注意的是，reduce函数还采用了第二个参数作为初始值，该参数将在第一时间传递给回调函数.

A reduce works by taking an array and running a function on each item. This "callback" function receives the value that the previous function returns, processes it in some way, then returns a new value. Worth noting, the reduce function also takes a 2nd argument that acts as the initial value that will be passed to the callback function the first time.

array.reduce(callbackFunction, initialValue);

这是一个用来对数组求和的reduce的例子.

Here's an example of reduce being used to sum an array.

var result = [1,2,3,4,5,6,7,8,9,10].reduce(function(accumulator, currentValue) {
  return accumulator + currentValue;
}, 0); // start with an initial value of 0
console.log(result);

使用ES6语法，可以将其进一步简化为单一格式

Using ES6 syntax, this can be further simplified to a one-liner

var result = [1,2,3,4,5,6,7,8,9,10].reduce((accumulator, currentValue) => accumulator + currentValue, 0);
console.log(result);

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