How to get distinct values from 2 different columns in the same list - list

Question

So as you can see from the code bellow i have a list object named Matches, from which i would like to get a single list of the distinct teams, both from HomeTeam and AwayTeam. I'm trying to use LINQ and i can get a list of distinct teams if i only use HomeTeam parameter or AwayTeam parameter but not both together.
Thank you.
public class Match
{
public int ID { get; set; }
public string Country { get; set; }
public string Championship { get; set; }
public string Seasson { get; set; }
public DateTime MatchDate { get; set; }
public string HomeTeam { get; set; }
public int HomeScore { get; set; }
public int AwayScore { get; set; }
public string AwayTeam { get; set; }
}
private List<Match> Matches;
Matches = dataAccess.GetAllMatches();
I'm Trying to do something like that:
result = Matches.Select(HomeTeam, AwayTeam).Distinct().ToList();

Answer 1

At the risk that this smells like homework, a hint rather than code. Get your Home teams, Union your Away teams and apply a Distinct to the result.

Answer 2

So i finally come up with this solution.
Notice that now i need also to get not only the team but the country which the team belongs to.
public class Team
{
public string Name { get; set; }
public string Country { get; set; }
}
So Union really do the job here but since now i need to get it as an anonymous type... here is the code:
List<Team> teams = new List<Team>();
var result = Matches.Select(x => new { Name = x.HomeTeam, Country = x.Country }).Union(Matches.Select(x => new { Name = x.AwayTeam, Country = x.Country })).ToList();
foreach (var record in result)
{
teams.Add(new Team { Name = record.Name, Country = record.Country });
}
return teams;
I would prefer this way:
List<Team> teamsResult = Matches.Select(x => new Team { Name = x.HomeTeam, Country = x.Country }).Union(Matches.Select(x => new Team { Name = x.AwayTeam, Country = x.Country })).ToList();
But this way get duplicates so i will stick with the first example for now.
Do you think it is the more elegant way to go?
Thank you.

Answer 3

You can take advantage of GroupBy, like this:
IEnumerable<Team> teams = Matches.GroupBy(m => new { m.AwayTeam, m.HomeTeam, m.Country })
.Select(
g =>
new[]
{
new Team {Country = g.Key.Country, Name = g.Key.AwayTeam},
new Team {Country = g.Key.Country, Name = g.Key.HomeTeam}
})
.SelectMany(x => x)
.GroupBy(t => new { t.Name, t.Country })
.Select(g => new Team { Name = g.Key.Name, Country = g.Key.Country });