Any better way for converting array to concurrent dictionary using linq or IEnumerable?

Question

I have an Array of Person object and I want to convert it to a ConcurrentDictionary. There is extension method for converting an Array to a Dictionary. Is there any extension method for converting an Array to a ConcurrentDictionary?

public class Person
{
    public Person(string name, int age)
    {
        Name =name;
        Age = age;
    }

    public string Name { get; set; }
    public int Age { get; set; }
}

Dictionary<int, Person> PersonDictionary = new Dictionary<int, Person>(); 
Person[] PersonArray = new Person[]
{
    new Person("AAA", 30),
    new Person("BBB", 25),
    new Person("CCC",2),
    new Person("DDD", 1)
};

PersonDictionary = PersonArray.ToDictionary(person => person.Age);

Any similar extension method/lambda expression for converting an Array to a ConcurrentDictionary?

Answer 1

Sure, use the constructor that accepts an IEnumerable<KeyValuePair<int,Person>>:

var personDictionary = new ConcurrentDictionary<int, Person>
                       (PersonArray.ToDictionary(person => person.Age));

var infers the type to ConcurrentDictionary<int,Person>.

If you're going to create an extension method, as Wasp suggested, I would recommend using the following version which offers a somewhat more fluent syntax:

public static ConcurrentDictionary<TKey, TValue> ToConcurrentDictionary<TKey, TValue> 
(this IEnumerable<TValue> source, Func<TValue, TKey> valueSelector)
{
    return new ConcurrentDictionary<TKey, TValue>
               (source.ToDictionary(valueSelector));
}

The usage is similar to the ToDictionary, creating a consistent feel:

var dict = PersonArray.ToConcurrentDictionary(person => person.Age);

Answer 2

You can write your own extension method very easily, for example like these:

public static class DictionaryExtensions
{
    public static ConcurrentDictionary<TKey, TValue> ToConcurrentDictionary<TKey, TValue>(
        this IEnumerable<KeyValuePair<TKey, TValue>> source)
    {
        return new ConcurrentDictionary<TKey, TValue>(source);
    }

    public static ConcurrentDictionary<TKey, TValue> ToConcurrentDictionary<TKey, TValue>(
        this IEnumerable<TValue> source, Func<TValue, TKey> keySelector)
    {
        return new ConcurrentDictionary<TKey, TValue>(
            from v in source 
            select new KeyValuePair<TKey, TValue>(keySelector(v), v));
    }

    public static ConcurrentDictionary<TKey, TElement> ToConcurrentDictionary<TKey, TValue, TElement>(
        this IEnumerable<TValue> source, Func<TValue, TKey> keySelector, Func<TValue, TElement> elementSelector)
    {            
        return new ConcurrentDictionary<TKey, TElement>(
            from v in source
            select new KeyValuePair<TKey, TElement>(keySelector(v), elementSelector(v)));
    }
}

Answer 3

There is a constructor that takes IEnumerable<KeyValuePair<TKey,TValue>>

IDictionary<int,Person> concurrentPersonDictionary = 
  new ConcurrentDictionary<int,Person>(PersonArray.ToDictionary(person => person.Age));