linq unique by property in csharp

To select distinct elements based on one property of an object using LINQ in C#, you can use the Distinct() method with a lambda expression as a parameter.

Assuming a class Person with a Name property, the following snippet would return all unique names:

main.cs
List<Person> people = new List<Person>() {
    new Person { Name = "John", Age = 25 },
    new Person { Name = "Jane", Age = 20 },
    new Person { Name = "John", Age = 30 },
    new Person { Name = "Joe", Age = 25 },
};

var uniqueNames = people.Select(p => p.Name).Distinct();

foreach (var name in uniqueNames) {
    Console.WriteLine(name);
    // Output: John Jane Joe
}
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In this example, we select the Name property of each Person object using the Select() method, and then call Distinct() on the resulting sequence to get only unique names.