Radio default checked

I have a radio list group for different payment methods. Also have almost the same structure for shipping methods. I am looking for solution one of the displayed radio in the radio-group to be checked by default.

<ion-list radio-group [(ngModel)]="form.payment_method" (ngModelChange)="changePayment()">
        <ion-item *ngFor="let method of form.payment | keys">
          <ion-label {{method.value.title}} >
          </ion-label>
          <ion-radio value="{{method.value.id}}">
          </ion-radio>
        </ion-item>
      </ion-list>

Could you elaborate a little bit on what you want to achieve and what your problem is? Check default radio, could you elaborate on that?

found this solution.
Because the value of the radio is the payment id
in constructor of the export class i’ve just added this property
this.form.payment_method = “cod”; // cod is the id of cash on delyvery