I have searched Google and can\'t find anything on this.
I have this code.
Only one answer by Srivathsa Harish Venkataramana mentioned track by which is indeed a solution for this!
Here is an example along with Plunker (link below) of how to use track by in select ng-options:
If selectedCity is defined on angular scope, and it has id property with the same value as any id of any city on the cities list, it'll be auto selected on load.
Here is Plunker for this: http://plnkr.co/edit/1EVs7R20pCffewrG0EmI?p=preview
See source documentation for more details: https://code.angularjs.org/1.3.15/docs/api/ng/directive/select