How do I join two collections in C# using LINQ?

How do I join two collections in C# using LINQ?

You can use the Join method in LINQ to join two collections based on a common key. Would you like an example?

Yes, please provide an example of joining two lists.

Sure! Here's a simple example:

var list1 = new List<Person> { new Person { Id = 1, Name = "John" }, new Person { Id = 2, Name = "Jane" } };
var list2 = new List<Order> { new Order { PersonId = 1, Product = "Book" }, new Order { PersonId = 2, Product = "Pen" } };

var joined = from p in list1
             join o in list2 on p.Id equals o.PersonId
             select new { p.Name, o.Product };

What if I want to perform a left join instead?

For a left join, you can use the GroupJoin method along with SelectMany. Would you like to see that example?