How to get row index in material table Angular

How to get row index in material table angular

 <td mat-cell *matCellDef="let row">                                                                            
   <mat-checkbox (click)="$event.stopPropagation()"                                                                                
     (change)="$event ? selection.toggle(row) : null;isSomeSelected()"                                                                               
     [checked]="selection.isSelected(row)">                                                                           
 </mat-checkbox></td>