C# SelectMany example

Flatten.cs

Lease[] leases =
    { new Lease { Leasee = "David",
          Assets = new List<string>{ "Workstation18", "Laptop5" } },
      new Lease { Leasee = "Pawel",
          Assets = new List<string>{ "Workstation30" } },
      new Lease { Leasee = "Rhys",
          Assets = new List<string>{ "Workstation24", "Headset3" } },
      new Lease { Leasee = "Karen",
          Assets = new List<string>{ "Laptop31", "MS-Keyboard", "Headset2" } } };

foreach (var i in Flatten(leases))
{
    Console.WriteLine("Leasee: {0}, Asset: {1}", i.Leasee, i.Asset);
}

static IEnumerable<LeaseRow> Flatten(Lease[] leases)
{
    return leases
        .SelectMany(lease => lease.Assets,
                (lease, asset) => new { lease, asset })
        .Select(leaseAndAsset =>
                new LeaseRow {
                    Leasee = leaseAndAsset.lease.Leasee,
                    Asset = leaseAndAsset.asset
                }
        );
}

record struct Lease
{
    public string Leasee { get; set; }
    public IList<string> Assets { get; set; }
}

record struct LeaseRow
{
    public string Leasee { get; set; }
    public string Asset { get; set; }
}

Based on the MSDN doco for SelectMany