使用reverse（）JavaScript求和两个最高值
[英]Sum two highest values using reverse() javascript
问题描述
How do I sum the two highest values from a list of inputs using JavaScript? 
如何使用JavaScript将输入列表中的两个最大值相加？
I've tried the below, but I get 4 instead of 5: 我尝试了以下方法，但得到的是4分而不是5分：
<table id="tableID"> <tr> <td> <input name="name" class="compulsory1" type="text" value="1" /> </td> <td> <input name="name1" class="compulsory1" type="text" value="3" /> </td> <td> <input name="name2" class="compulsory1" type="text" value="2" /> </td> <td> <script type="text/javascript"> var tdsCompulsory = document.getElementsByClassName('compulsory1'); var len = tdsCompulsory.length; var cDatax = []; var cData = cDatax.reverse(); sum = 0; for(var i = 0; i < 2; i++){ cData.push(tdsCompulsory[i].value); sum += +tdsCompulsory[i].value; } alert (sum); </script> </td> </tr> </table>
5 个解决方案
解决方案1
1 已采纳 2016-07-29 10:05:56
First you find the two highest values, and then sum them together. 首先，找到两个最大值，然后将它们求和。 I'd probably do it something like this: 我可能会这样做：
document.getElementById("the-button").onclick = function() { // Get the values as numbers var values = Array.prototype.map.call( document.getElementsByClassName('compulsory1'), function(input) { return +input.value; // + converts to number } ); // Put them in order *highest* to *lowest* values.sort(function(left, right) { return right - left; }); // Add the first two var result = values[0] + values[1]; console.log(values[0] + " + " + values[1] + " = " + result); };
<input name="name" class="compulsory1" type="text" value="1" /> <input name="name1" class="compulsory1" type="text" value="3" /> <input name="name2" class="compulsory1" type="text" value="2" /> <input id="the-button" type="button" value="Run">
More about that Array.prototype.map.call thing in this answer about looping through arrays and array-like things. 这个答案中有关Array.prototype.map.call的更多信息，涉及遍历数组和类似数组的事物。
But if you specifically want to use reverse , you'd do that after the sort : 但是，如果您特别想使用reverse ，则可以在sort之后执行：
document.getElementById("the-button").onclick = function() { // Get the values as numbers var values = Array.prototype.map.call( document.getElementsByClassName('compulsory1'), function(input) { return +input.value; // + converts to number } ); // Put them in order lowest to highest values.sort(function(left, right) { return left - right; }); // Then reverse that values.reverse(); // Add the first two var result = values[0] + values[1]; console.log(values[0] + " + " + values[1] + " = " + result); };
<input name="name" class="compulsory1" type="text" value="1" /> <input name="name1" class="compulsory1" type="text" value="3" /> <input name="name2" class="compulsory1" type="text" value="2" /> <input id="the-button" type="button" value="Run">
解决方案2
1 2016-07-29 10:14:14
You could try something like following: 您可以尝试如下操作：
function PickTwoHighestCtrl() { let els = document.querySelectorAll(".compulsory1"); let values = Array.prototype.map.call(els, (el) => { return Number(el.value) || 0; }); let highest = Math.max.apply(Math, values); let secondHighest = Math.max.apply( Math, values.filter(e => e !== highest) ); console.log("Two highest values are:", highest, secondHighest, "and their sum is", highest + secondHighest) } document.addEventListener("DOMContentLoaded", PickTwoHighestCtrl);
<input class="compulsory1" type="text" value="1" /> <input class="compulsory1" type="text" value="3" /> <input class="compulsory1" type="text" value="2" />
解决方案3
1 2016-07-29 10:17:41
<html>
<head>
<script>
var tdsCompulsory = document.getElementsByClassName('compulsory1');
var cDatax = [];
sum = 0;
for(var i = 0; i < 3; i++){
cDatax.push(tdsCompulsory[i].value);
}
// let's convert it to a real array of numbers, not of strings :
var intArray = cDatax.map(Number);
var max = Math.max.apply(null, intArray);
// now let's sort it and take the second element :
var second = intArray.sort(function(a,b){return b-a})[1];
var sum = max+second;
alert(sum)
</script>
</head>
<body>
<table id="tableID">
<tr>
<td> <input name="name" class="compulsory1" type="text" value="1" /> </td>
<td> <input name="name1" class="compulsory1" type="text" value="3" /> </td>
<td> <input name="name2" class="compulsory1" type="text" value="2" /> </td>
<td>
</td>
</tr>
</table>
</body>
</html>
解决方案4
1 2016-07-29 10:21:34
You can try something like this: 您可以尝试如下操作：
Steps 脚步
- Get all elements 获取所有元素
- Get their values. 获得他们的价值观。 Note, since you expect values to be number, yuo should parse them as well. 注意，由于您希望值是数字，因此yuo也应解析它们。
- Sort value array in descending order instead of
.sort+.reverse以降序而不是.sort+.reverse对值数组进行排序 - Calculate your sum 计算你的总和
Sample 样品
// Get all elements var tdsCompulsory = document.getElementsByClassName('compulsory1'); // Get values from all elements var valArr = Array.prototype.map.call(tdsCompulsory, function(el) { return parseInt(el.value) }); // Sort value array in descending order var cDatax = valArr.sort(function(a, b) { return ba }); var sum = cDatax[0] + cDatax[1]; console.log(sum)
<table id="tableID"> <tr> <td> <input name="name" class="compulsory1" type="text" value="1" /> </td> <td> <input name="name1" class="compulsory1" type="text" value="3" /> </td> <td> <input name="name2" class="compulsory1" type="text" value="2" /> </td> </tr> </table>
解决方案5
1 2016-07-29 10:22:43
var tdsCompulsory = document.getElementsByClassName('compulsory1'), cDatax = Array.prototype.map.call(tdsCompulsory, function(el) { return parseInt(el.value) || 0; }), sum = 0; cDatax .sort(function(a, b){ return a - b; }) .reverse(); sum = cDatax[0] + cDatax[1]; console.log(sum);
<table id="tableID"> <tr> <td><input name="name" class="compulsory1" type="text" value="1" /></td> <td><input name="name1" class="compulsory1" type="text" value="3" /></td> <td><input name="name2" class="compulsory1" type="text" value="2" /></td> </tr> </table>
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