title: How can I check if the first character of a string it is a number as a condition in *ngIf
body: <p>I am trying to check if a document name it is coming with the first char as a number. I am not able to make my code go in and display &quot;Dummy string&quot;. I tried with this two options but it is not working.</p>
  <pre><code>1.
  let documentPDF = &quot;6487954.pdf&quot;
  &lt;ng-container *ngIf=&quot;Character.isDigit(ParseInt(documentPDF.charAt(0))) == false&quot;&gt;
           Dummy string
  &lt;/ng-container&gt;
  
  2.
  let document = &quot;6487954.pdf&quot;
  &lt;ng-container *ngIf=&quot;isNaN(ParseInt(documentPDF.charAt(0))) == false&quot;&gt;
           Dummy string
  &lt;/ng-container&gt;
  
  </code></pre>
  <p>Thank you for your help.</p>