C# Enumerable Distinct(IEnumerable, IEqualityComparer)
Description
Returns distinct
elements from a sequence by using a specified IEqualityComparer
Syntax
public static IEnumerable<TSource> Distinct<TSource>(
this IEnumerable<TSource> source,
IEqualityComparer<TSource> comparer
)
Parameters
TSource- The type of the elements of source.source- The sequence to remove duplicate elements from.comparer- An IEqualityComparerto compare values.
Returns
Returns distinct
elements from a sequence by using a specified IEqualityComparer
Example
The following example shows how to implement an equality comparer that can be used in the Distinct method.
//from ww w . j a va 2 s.co m
using System;
using System.Linq;
using System.Collections.Generic;
public class MainClass{
public static void Main(String[] argv){
Product[] products = { new Product { Name = "apple", Code = 9 },
new Product { Name = "orange", Code = 4 },
new Product { Name = "apple", Code = 9 },
new Product { Name = "lemon", Code = 12 } };
IEnumerable<Product> noduplicates =
products.Distinct(new ProductComparer());
foreach (var product in noduplicates)
Console.WriteLine(product.Name + " " + product.Code);
}
}
public class Product
{
public string Name { get; set; }
public int Code { get; set; }
}
class ProductComparer : IEqualityComparer<Product>
{
public bool Equals(Product x, Product y)
{
return x.Name == y.Name;
}
public int GetHashCode(Product product)
{
return product.Name.GetHashCode();
}
}
The code above generates the following result.
