public static void Execute()
{
// Most of the time you will use lambda expressions with LINQ
// However, it can serve useful purposes in lots of other ways
//
// Example 01: Mapping objects
// using lambda expressions, you can easily map one object to another
Person person = PersonFactory.Get();
var dto = MapToDto(person, p =>
{
return(new PersonDto {
ConcatenatedInfo = p.Name + p.Age + p.Cat.Name
});
});
// the above code might look a little silly by itself, but combined with factories and code that uses Generics, it can be useful
//
// Example 02: Extending code in useful ways
// we can imagine some existing code that might be extensible in some way to allow for special modifications
PersonDto customPerson = new PersonDto(s =>
{
return("SUPER COOL " + s);
});
customPerson.ConcatenatedInfo = "Justin";
Console.WriteLine(customPerson.ConcatenatedInfo);
//
// Assignment: Think of a cool way you can use lambda expressions and implement something
// It can be whatever you want
//
}
public static void Execute()
{
// We have a "person factory" which gives us a bunch of people
// We'll imagine that this is like our "database access layer"
// Each person also has a cat
// In some cases, we will want information about people, and sometimes we might need to filter information
// based on both people and cats!
var people = PersonFactory.Get(50);
// to help you get started, I'll show you how to get the top 10 oldest people
var oldestPeople = people
.OrderByDescending(p => p.Age) // .OrderBy() and .OrderByDescending are like ORDER BY in SQL
.Take(10); // Take() is like TOP in SQL
foreach (var person in oldestPeople)
{
Console.WriteLine("Person: " + person.Name + " is " + person.Age + " years old. Their cat is " + person.Cat.Age + " years old");
}
//
// Now the fun part begins! You get to do it yourself
//
// 1) Get the average person age
// 2) Get the 1 person with the oldest cat
// 3) Get all cats younger than 20
// 4) Get all people with "z" in their name
// 5) Select the first cat name with a "W" in it (only the name, not the whole cat)
// 6) Get the 10th - 20th oldest people (hint: use Skip and Take)
}