Minimum of a struct-Array in C#

I used a Select() to perform a calculation on each member of an array of structs and now want to have the member for which a certain attribute is minimal. I wanted to use something like Min() on the selected sequence, but I don't know how to return the full struct, rather than only the attribute that is minmal.

From stackoverflow

• If i understand correctly, i'd say: use delegates...

  Here's an Example from Craig Murphy

  public class Person
  {
            public int age;
            public string name;
            public Person(int age, string name)
            {
                     this.age = age;
                     this.name = name;
            }
  }
  // everyone under 25:
  List<person> young = people.FindAll(delegate(Person p) { return p.age < 25; });
  
  // sort your list: 
  people.Sort(delegate(Person p1, Person p2)
     { return p1.age.CompareTo(p2.age); });
  

• Sounds like you want to use MinBy from MoreLINQ:

  public static TSource MinBy<TSource, TKey>(this IEnumerable<TSource> source,
      Func<TSource, TKey> selector, IComparer<TKey> comparer)
  {
      source.ThrowIfNull("source");
      selector.ThrowIfNull("selector");
      comparer.ThrowIfNull("comparer");
      using (IEnumerator<TSource> sourceIterator = source.GetEnumerator())
      {
          if (!sourceIterator.MoveNext())
          {
              throw new InvalidOperationException("Sequence was empty");
          }
          TSource min = sourceIterator.Current;
          TKey minKey = selector(min);
          while (sourceIterator.MoveNext())
          {
              TSource candidate = sourceIterator.Current;
              TKey candidateProjected = selector(candidate);
              if (comparer.Compare(candidateProjected, minKey) < 0)
              {
                  min = candidate;
                  minKey = candidateProjected;
              }
          }
          return min;
      }
  }
  

  ThrowIfNull is defined as an extension method:

  internal static void ThrowIfNull<T>(this T argument, string name)
      where T : class
  {
      if (argument == null)
      {
          throw new ArgumentNullException(name);
      }
  }
  

  Hosam Aly : How is this different from `source.OrderBy(selector, comparer).FirstOrDefault()`?

  configurator : Efficiency. OrderBy is O(n * lg n), this is O(n) I believe.

  Hosam Aly : You're right @configurator. I have just taken a look at the implementation of OrderBy, and I agree. +1 Jon.

• How about ordering by your "value" and taking the first entry (the minimum value):

  Persons.OrderBy(p => p.Age).FirstOrDefault();
  

  That is of course if you only want one item (which is what you state).

  Alternatively:

  from p in Persons
  where p.Age == Persons.Select(p1 => p1.Age).Min()
  select p;
  

  Will get you all items with minimum value.

  Hosam Aly : +1. I would have done it in the same way (at least for one item).

  Hosam Aly : Jon's answer has better performance, but this one is more "built-in".