title: How to get first letter of string in flutter dart?
body: <p>How do I get the first character of a string in dart flutter.</p>
  
  <p>For example,a string having a value "Hello World" should return only "H".
  I am fetching data from my firestore database.
  My code is:</p>
  
  <pre><code>searchByName(String searchField) {
    return Firestore.instance
        .collection('posts')
        .where('description',
        isEqualTo: searchField.substring(0, 1).toUpperCase())
        .getDocuments();
  }
  </code></pre>
  
  <p>I want to get the first letter from the data that I recieve from 'description' field in above code.</p>