循环遍历数组并返回所有值的总和
[英]Loop through array and return sum of all values
问题描述
What I want to do is have numbers inputted by user and the sum of the numbers returned. 
我想要做的是用户输入的数字和返回的数字之和。 My logic is as follows: 我的逻辑如下：
- User inputs string 用户输入字符串
- String is split to array 字符串被拆分为数组
- Loop through array and sum all numbers 循环遍历数组并对所有数字求和
- Return sum 归还总和
And here is the code I have so far: 这是我到目前为止的代码：
<script type='text/javascript'>
var val=document.getElementById('userInput').value;
var temp=val.split(" ");
function sum() {
for(var i=0, MISSING THIS BIT
document.getElementById('resultSum').innerHTML=MISSING THIS BIT;
}
</script>
<form name="input">
<textarea name="userInput" rows=20 cols=20></textarea>
<input name="Run" type=Button value="run" onClick="sum()">
<form name="resultSum"><input type=Text>
I admit with humility that this is mostly probably wrong and appreciate anybody's time and effort. 我谦虚地承认这很可能是错误的，并且感谢任何人的时间和精力。
UPDATE: I have done as suggested and I get the following error on my code below: 更新：我已按照建议完成，我在下面的代码中收到以下错误：
Message: 'document.getElementById(...)' is null or not an object Line: 16 Char: 1 Code: 0
<html>
<script type='text/javascript'>
function sum(){
var val = document.getElementById('userInput').value;
var temp = val.split(" ");
var total = 0;
var v;
for(var i = 0; i < temp.length; i++) {
v = parseFloat(temp[i]);
if (!isNaN(v)) total += v;
}
document.getElementById('resultSum').innerHTML=total;
}
</script>
<form name="input">
<textarea name="userInput" rows=20 cols=20></textarea>
<input name="Run" type=Button value="run" onClick="sum()">
<form name="resultSum"><input type=text>
<html>
Any suggestions? 有什么建议么？ Thanks to all for being comprehensive - I have read both examples and understand the process now! 感谢所有人的全面 - 我已经阅读了这两个例子并立即了解了这个过程！
4 个解决方案
解决方案1
8 已采纳 2011-09-07 01:45:09
You want a basic loop to convert and add each item. 您需要一个基本循环来转换和添加每个项目。
I have also cleaned up your HTML a ton. 我还清理了你的HTML。 You didn't have any proper closing tags. 你没有任何正确的结束标签。 I have also changed all of the 'name' attributes to 'id' attributes so that 'getElementById' would work properly, which I missed on my first pass. 我还将所有'name'属性更改为'id'属性，以便'getElementById'能够正常工作，这是我在第一次传递时错过的。
<html>
<head>
<script type='text/javascript'>
function sum(){
var val = document.getElementById('userInput').value;
var temp = val.split(" ");
var total = 0;
var v;
for(var i = 0; i < temp.length; i++) {
v = parseFloat(temp[i]);
if (!isNaN(v)) total += v;
}
document.getElementById('resultSumValue').value = total;
}
</script>
</head>
<body>
<form id="input">
<textarea id="userInput" rows=20 cols=20></textarea>
<input id="Run" type=Button value="run" onClick="sum()" />
</form>
<form id="resultSum">
<input id="resultSumValue" type="text" />
</form>
</body>
</html>
This will also ignore any values that are 'NaN' (Not a Number). 这也将忽略任何'NaN'（非数字）的值。
If you want the numbers to only be integers (no decimals), change parseFloat to parseInt. 如果您希望数字只是整数（无小数），请将parseFloat更改为parseInt。
解决方案2
2 2011-09-07 01:47:43
Here is an outline, but I think it's worth writing it yourself to learn. 这是一个大纲，但我认为值得自己写一下来学习。
- split() returns an array of characters. split（）返回一个字符数组。 You can get the length of that array with temp.length 您可以使用temp.length获取该数组的长度
- You'll want to loop over every element of that array. 您将要遍历该数组的每个元素 。
- Because "1" + "2" = "12" in javascript, you need to convert your characters to integers 因为javascript中的“1”+“2”=“12”，您需要将字符转换为整数
- Keep a running total of the sums, and add to it at each iteration of the loop, maybe validating that each number is a real number 保持总和的总和，并在循环的每次迭代中添加它，可能验证每个数字是实数
解决方案3
0 2011-09-07 01:45:32
First start by declaring a variable set to 0 before the for loop. 首先在for循环之前声明变量设置为0。 Iterate over each element in the array (array.length) adding to the variable you set before the for loop. 迭代数组中的每个元素（array.length），添加到for循环之前设置的变量。
解决方案4
0 2011-09-07 04:38:20
<html>
<head>
<title>sum input</title>
<style>
p, textarea,input{font-size:24px}
textarea,input{text-align:right}
</style>
<script>
function sum(){
var val= document.getElementById('userInput').value.replace(/^\D+|D+$/g,'');
document.getElementById('resultSum').value= eval(val.replace(/\D+/g,'+'));
}
</script>
</head>
<body>
<p>Enter a series of numbers :<br>
<textarea id="userInput" rows="10" cols="10"></textarea><br>
<input id="Run" type="button" value="Sum" onClick="sum()">
<input id="resultSum" type="text" readOnly>
</p>
</body>
</html>
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