title: How to remove all the numbers from an array?
body: <p>I'm trying to remove all the numbers from an array. The loop works exactly as I want, but the splice() method still skips some elements for some reason.</p>
  
  <pre><code>let arr = ['1', '2', '3', '4', '5', 'notanumber', '6'];
  
  for (let element of arr) {
    let index = arr.indexOf(element);
    let check = isNaN(element);
    if (check === false) {
      arr.splice(index, 1);
    };
  };
  
  console.log(arr);
  </code></pre>
  
  <p>Expected output is: <code>['notanumber']</code><br>
  Current output is:  <code>['2', '4', 'notanumber']</code></p>