rx java - How can i change a Field in a List of Objects with RXJava/Android -

i have list mypersonlist wanna fill name , city of every item. have id's filled. create foreach , call fillpersondata how can observables? know there map() , flatmap() ... don't

class person{    int id;    string name;    string city; }  list<person> mypersonlist; 

what have observable list person data filled function:

class personutil{        public person fillpersondata(person person){           ... fill person data...       } } 

update:

sorry fault: didn't need observable subscribe on , not person class has function named fillpersondata()... let me have personutil...

so need return it:

observable<list<person>> myobservable  = ...the magic code :-) 

update 2:

i tried answer frhack , works. completeness because work in android studio without lambdas here code without lambdas:

 observable<person> observable =  observable.from(personlist)             .filter(new func1<person, boolean>() {                  @override                 public boolean call(person person) {                     personutil.fillmaildata(person);                     return true;                 }              }); 

i hope right way... if not... tell me , change update2!!

list<person> personlist = new arraylist<person>(); // populate personlist observable.from(personlist).foreach((person)-> {         person.setname(name);         person.setcity(city); }); 

alternate version:

list<person> personlist = new arraylist<person>(); // populate personlist observable.from(personlist).foreach((person)-> p.fillpersondata() ); 

alternate version:

list<person> personlist = new arraylist<person>(); // populate personlist observable<person> observable =  observable.from(personlist)    .filter((person) -> {             person.setname(name);            //personutil.fillpersondata(person)                  return true;         });  observable.foreach((pp)->system.out.println(pp));