I have list of type Person which has 3 properties Id, Name, Age
var per1 = new Person((1, "John", 33);
var per2 = new Person((2, "Anna", 23);
var persons = new List<Person>();
For one match:
var match = persons.Single(p => your condition);
For many matches, use
persons.Where(condition). There are also many variants of picking just one person, such as FirstOrDefault, First, Last, LastOrDefault, and SingleOrDefault. Each has slightly different semantics depending on what exactly you want.