Given:
class Program
{
private static readonly List<(int a, int b, int c)> Map = new List<(int a, int b, int c)>()
{
(1, 1, 2),
(1, 2, 3),
(2, 2, 4)
};
static void Main(string[] args)
{
var result = Map.FirstOrDefault(w => w.a == 4 && w.b == 4);
if (result == null)
Console.WriteLine("Not found");
else
Console.WriteLine("Found");
}
}
In the above example, a compiler error is encountered at line if (result == null)
.
CS0019 Operator '==' cannot be applied to operands of type '(int a, int b, int c)' and '<null>'
How would I go about checking that the tuple is found prior to proceeding in my "found" logic?
Prior to using the new c# 7 tuples, I would have this:
class Program
{
private static readonly List<Tuple<int, int, int>> Map = new List<Tuple<int, int, int>>()
{
new Tuple<int, int, int> (1, 1, 2),
new Tuple<int, int, int> (1, 2, 3),
new Tuple<int, int, int> (2, 2, 4)
};
static void Main(string[] args)
{
var result = Map.FirstOrDefault(w => w.Item1 == 4 && w.Item2 == 4);
if (result == null)
Console.WriteLine("Not found");
else
Console.WriteLine("Found");
}
}
Which worked fine. I like the more easily interpreted intention of the new syntax, but am unsure on how to null check it prior to acting on what was found (or not).
null
. So you could check for that instead.Any
or xanatos's trick withTake(1).ToArray()
to differentiate between not found and found, but just happens to match the default.