prompter: Using C# and LINQ, please show me an example of how to sort a collection of objects based on one of their properties, and returning only unique results.

assistant: I can show you an example of how to sort a collection of objects based on one of their properties, returning only the unique results.

Let us suppose that we have 'Human' class as follows:
```
public class Human
{
    public string Name { get; set; }
    public char Gender { get; set; }
    public int Age { get; set; }
}
```


Suppose that you have Collection as this:
```
List<Human> humans = new List<Human>()
{
    new Human() { Name = "Alisha", Gender = 'F', Age = 22 },
    new Human() { Name = "Manish", Gender = 'M', Age = 26 },
    new Human() { Name = "Ashim", Gender = 'M', Age = 24 },
    new Human() { Name = "Sanjana", Gender = 'F', Age = 20}
};
```


The following code sorts the collection based on the 'Age' property and returns only the unique objects from collection.
```
var sortedHumans = humans.OrderBy(h => h.Age).Distinct();
```


You can iterate over the sorted collection to print the properties as follows:
```
foreach (Human human in sortedHumans)
{
    Console.WriteLine($"{human.Name} ({human.Gender}, {human.Age})");
}
```

assistant: Sure! Here's an example of how to sort a collection of objects based on one of their properties, and returning only unique results using LINQ in C#:

Suppose we have a collection of Person objects with the properties Name, Age, and City. We want to sort the collection based on the Age property and return only unique City values. Here's how we can do it:

```c#
using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        // Create a list of Person objects
        List<Person> people = new List<Person>()
        {
            new Person { Name = "Alice", Age = 28, City = "New York" },
            new Person { Name = "Bob", Age = 32, City = "Boston" },
            new Person { Name = "Charlie", Age = 28, City = "Los Angeles" },
            new Person { Name = "Dave", Age = 35, City = "Seattle" },
            new Person { Name = "Eve", Age = 32, City = "Chicago" },
        };

        // Sort the list by Age and return only unique City values
        var uniqueCities = people.OrderBy(p => p.Age)
                                 .Select(p => p.City)
                                 .Distinct();

        // Print the unique cities
        foreach (var city in uniqueCities)
        {
            Console.WriteLine(city);
        }
    }
}

// Define the Person class
class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
    public string City { get; set; }
}
```

In this example, we first create a list of Person objects with some sample data. We then use LINQ to sort the list by the Age property in ascending order, and select only the City property for each Person object. We then use the Distinct() method to return only the unique City values.

Finally, we print the unique cities to the console using a foreach loop.

This should give you a basic idea of how to sort a collection of objects based on one of their properties and return only unique results using LINQ in C#.

assistant: Sure:

`documents.GroupBy(p => p.Name).Select(g => g.First()).ToList()`

This code is useful when you know that documents with the same names are duplicates. So you take only the first one.

You can also use:

`documents.OrderBy(o => o.Name).Distinct()`

But you will have to implement the IEquatable interface to define how to compare documents.