title: Get Tuple from a collection by one of its values?
body: <p>Is there a way to get a Tuple from a collection by only one of the Tuple's values? For example when I use this Tuple struct:</p>
  
  <pre><code>public struct Tuple&lt;T1, T2&gt; {
      public readonly T1 Item1;
      public readonly T2 Item2;
      public Tuple(T1 item1, T2 item2) { Item1 = item1; Item2 = item2;} 
  }
  </code></pre>
  
  <p>Is there a way to get all Tuples that have a specific item (Item1 or Item2). I thought about some kind of HashMap since looping through a list of tuples and checking each tuple for a match is quite inefficient for large datasets.</p>