Querying a List by Lambda Expression

Suppose you have a class “Person” and a list “lstPersonsInCity” is a collection of persons in a city as following:

Class Person

{

Public string SSN;

public string Name;

public string Address

public int Age;

}

List<Person> lstPersonsInCity = new List<Person>();

Now you can do perform several types of queries in your list by using lambda expression in a very easy way. Some examples are shown below:

• // Grab Top 1000 old aged persons from the all the persons in city

List<Person> lstAgedPersonsInCity = lstPersonsInCity.FindAll(e =>

(e.Age >= 60)).Take(1000).ToList();

• // Remove all the persons record from list that have “SAM” name

lstPersonsInCity.RemoveAll(e => (e.Name == “SAM”));

• // Find the person whose SSN = 203456876 from the all the persons in city

Person oPerson = lstPersonsInCity.Find(e => (e.SSN == “203456876”));