Question

我在完成代码时遇到了一些困难。它工作得很好，除了我无法弄清楚如何将我的数组乘以一个百分比。这是我的代码：

<p>Click the button to get the sum of the numbers in the array.</p>
<button onclick="myFunction()">Try it</button>

<p>Sum of numbers in array: <span id="demo"></span></p>

<p>Amount with 7% tax added: <span id="percent"></span></p>
<script>
var numbers = [12.3, 20, 30.33];

function getSum(total, num) {
    return total + num;
}
function myFunction(item) {
    document.getElementById("demo").innerHTML = numbers.reduce(getSum);
}

function myFunction(item) {
    document.getElementById("percent").innerHTML = (numbers * .07);
}

</script>

感谢所有帮助！

Answer 1

当你问如何繁殖时（我假设你想要7％）答案就是

var numbers = [12.3, 20, 30.33];

numbers = numbers.map(function(i){
  return Math.round(i*.07 * 100)/100;
});

console.log(numbers);

Answer 2

与数组相乘总是得NaN。我想你需要得到总和的7%然后得到总和，然后通过乘以计算百分比。

numbers.reduce(getSum) * .07

<p>Click the button to get the sum of the numbers in the array.</p>
<button onclick="myFunction()">Try it</button>

<p>Sum of numbers in array: <span id="demo"></span>
</p>

<p>Amount with 7% tax added: <span id="percent"></span>
</p>
<script>
  var numbers = [12.3, 20, 30.33];

  function getSum(total, num) {
    return total + num;
  }

  function myFunction(item) {
    document.getElementById("demo").innerHTML = numbers.reduce(getSum);
  }

  function myFunction(item) {
    document.getElementById("percent").innerHTML = numbers.reduce(getSum) * .07;
  }
</script>

如何将数组乘以百分比？

2 个答案: