title: HTML : create a table with n number of rows using angular 8
body: <p>I want to create a table with 20 rows.</p>
  <p>I am getting some of the data from backend, say for 3 rows. for next 17 rows, cell for each row should be empty.</p>
  <p>using the below code will only give me the row as per the data which is 3 in number</p>
  <pre><code>&lt;table&gt;
      &lt;tr *ngFor=&quot;let group of groups&quot;&gt;
          &lt;td&gt;&lt;h1&gt;{{group.name}}&lt;/h1&gt;&lt;/td&gt;
      &lt;/tr&gt;
  &lt;/table&gt; 
  </code></pre>
  <p>I want to try sth like below, but syntax wise things are not working.</p>
  <pre><code>&lt;table&gt;
      &lt;tr *ngFor=&quot; let group of groups&quot;&gt;
          &lt;td&gt;&lt;h1&gt;{{group.name}}&lt;/h1&gt;&lt;/td&gt;
      &lt;/tr&gt;
     &lt;tr *ngFor=&quot;let x of 20 - groups.length&quot;&gt;
          &lt;td&gt;&lt;/td&gt;
      &lt;/tr&gt;
  &lt;/table&gt; 
  </code></pre>
  <blockquote>
  <p>20 - groups.length should be an array, but it is a number</p>
  </blockquote>