Angular 2 conditional ngFor

  <li *ngFor="let a of (condition ? array1 : array2)">
    <p>{{a.firstname}}</p>
    <p>{{a.lastname}}</p>
  </li>

You can make use of the ng-container which is not recognised by DOM, hence will only be used for a condition. See example below:

 <tr *ngFor="let company of companies">
        <ng-container *ngIf="company.tradingRegion == 1">
            <td>{{ company.name }}</td>
            <td>{{ company.mseCode }}</td>
         </ng-container>
  </tr>

The code above will: `

Display a list of all companies where the tradingRegion == 1

`