title: Check value in array exists Flutter dart
body: <p>I am trying to check condition </p>
  
  <pre><code>if (value in List) {
    exist
  } else { 
    not exist
  }
  </code></pre>
  
  <p>but nothing to help anyone having an idea then please share.</p>
  
  <pre><code>My List = _quantityController[];
  </code></pre>
  
  <p>itemId is integer</p>
  
  <p>i want to check my item id exists in my list array or not...Thanks!</p>