Apex get fields of ANY object

Question

I have a JSON response that returns a List which contains city names. I need to de-duplicate this list. Here is my apex:

    global void myLeadsCities(Map<String,Object> inputJsonMap) {
        Set<String> leadCities = new Set<String>();
        List<Object> objs = (List<Object>)inputJsonMap.get('leads');
        for (Object o : objs) {
//console.log(o);  //this returns example: {city=New York} or {city=Boston}, etc...
            //how do I get o.city
            //leadCities.add(o.city);
        }
    }

Apex doesn't recognize personName so it fails. How do I read a value from "ANY" Object type?

Answer 1

You have to cast to another Map:

for (Object o : objs) {
  Map<String, Object> leadFields = (Map<String, Object>)o;
  String city = (String)leadFields.get('city');
  System.debug(city);
}

Object (ANY) is the parent of all objects, and you can't really "do" anything with it. You need to cast it to a subtype (Boolean, Map, List, String, whatever) to get useful functionality with it.

You can use instanceOf to detect the runtime value of an Object. For JSON.deserializeUntyped, it will always be one of Boolean, String, Integer/Long, Double/Decimal, List<Object>, or Map<String, Object>.