我有问题添加一个数组的所有元素以及平均它们。我将如何做到这一点，并实现它与我目前的代码?元素的定义如下所示。
<script type="text/javascript">
//<![CDATA[
var i;
var elmt = new Array();
elmt[0] = "0";
elmt[1] = "1";
elmt[2] = "2";
elmt[3] = "3";
elmt[4] = "4";
elmt[5] = "7";
elmt[6] = "8";
elmt[7] = "9";
elmt[8] = "10";
elmt[9] = "11";
// Problem here
for (i = 9; i < 10; i++){
document.write("The sum of all the elements is: " + /* Problem here */ + " The average of all the elements is: " + /* Problem here */ + "<br/>");
}
//]]>
</script>
当前回答
var sum = 0;
for( var i = 0; i < elmt.length; i++ ){
sum += parseInt( elmt[i], 10 ); //don't forget to add the base
}
var avg = sum/elmt.length;
document.write( "The sum of all the elements is: " + sum + " The average is: " + avg );
只需要遍历数组，因为您的值是字符串，所以必须先将它们转换为整数。平均值就是数值的和除以数值的个数。
其他回答
如果你需要平均值并且可以跳过计算和的要求，你可以通过调用reduce来计算平均值:
// Assumes an array with only values that can be parsed to a Float
var reducer = function(cumulativeAverage, currentValue, currentIndex) {
// 1. multiply average by currentIndex to find cumulative sum of previous elements
// 2. add currentValue to get cumulative sum, including current element
// 3. divide by total number of elements, including current element (zero-based index + 1)
return (cumulativeAverage * currentIndex + parseFloat(currentValue))/(currentIndex + 1)
}
console.log([1, 2, 3, 4, 5, 6, 7, 8, 9, 10].reduce(reducer, 0)); // => 5.5
console.log([].reduce(reducer, 0)); // => 0
console.log([0].reduce(reducer, 0)); // => 0
console.log([].reduce(reducer, 0)); // => 0
console.log([,,,].reduce(reducer, 0)); // => 0
console.log([].reduce(reducer, 0)); // => 0
将for循环计数器设置为0....你得到了元素9，然后你就完成了。其他答案都是基础数学。使用一个变量来存储你的和(需要将字符串转换为整数)，然后除以你的数组长度。
ES6
Const average = arr => arr。Reduce ((p, c) => p + c, 0) / arr.length; Const result = average([4,4,5,6,6]);/ / 5 console.log(结果);
这是我的一个简单的求平均值的新手方法。希望这能帮助到一些人。
function numAvg(num){
var total = 0;
for(var i = 0;i < num.length; i++) {
total+=num[i];
}
return total/num.length;
}
HTML内容的平均值
使用jQuery或Javascript的querySelector，您可以直接访问格式化的数据…例子:
<p>Elements for an average: <span class="m">2</span>, <span class="m">4</span>,
<span class="m">2</span>, <span class="m">3</span>.
</p>
因此，使用jQuery
var A = $('.m')
.map(function(idx) { return parseInt($(this).html()) })
.get();
var AVG = A.reduce(function(a,b){return a+b}) / A5.length;
查看其他4种方法(!)来访问itens和平均它:http://jsfiddle.net/4fLWB/
