Distinct

Returns a collection that contains no duplicate entries according to comparer and hashCodeGetter functions.

If an element occurs multiple times in the collection then the later occurrences are discarded.

Internally this method uses a EqualityComparerBuilder<T> object.

Parameter	Returns
Func<T, T, bool> comparer Func<T, int> hashCodeGetter IEnumerable<T> source	int

Usage

Discarding duplicate entries

class Product {
    int Id {get; set;}
    string Name {get; set;}
    double Price {get; set;}
}

// products:
// |    Id    |    Name    |    Price    |
// |    1     |  Notebook  |     800     |
// |    2     |    Mouse   |      20     |
// |    3     |   Wallet   |      40     |
// |    4     |    Book    |      10     |
// |    5     | Smartphone |     400     |
// |    1     |  Notebook  |     800     |
// |    1     |  Notebook  |     800     |
// |    4     |    Book    |      10     |

IEnumerable<Product> result = products.Distinct(
    (product1, product2) => product1.Id == product2 == Id,
     product => product.Id.GetHashCode()
    );

// result:
// |    Id    |    Name    |    Price    |
// |    1     |  Notebook  |     800     |
// |    2     |    Mouse   |      20     |
// |    3     |   Wallet   |      40     |
// |    4     |    Book    |      10     |
// |    5     | Smartphone |     400     |