freeCodeCamp/guide/english/csharp/linq/to-dictionary/index.md

title
To Dictionary

ToDictionary

Greates a Dictionary from the DataSet;

Signature

Enumerable.ToDictionary<TSource, TKey> Method (IEnumerable<TSource>, Func<TSource, TKey>)

Example

var fruits = new List<Fruit>() {
    new Fruit() { Id = 1, Name = "Orange",     Color = "Orange", Quantity: 3   },
    new Fruit() { Id = 2, Name = "Strawberry", Color = "Red",    Quantity: 12  },
    new Fruit() { Id = 3, Name = "Grape",      Color = "Purple", Quantity: 25  },
    new Fruit() { Id = 4, Name = "Pineapple",  Color = "Yellow", Quantity: 1   },
    new Fruit() { Id = 5, Name = "Apple",      Color = "Red",    Quantity: 5   },
    new Fruit() { Id = 6, Name = "Mango",      Color = "Yellow", Quantity: 2   }
};

// Generates a Dictionary of Fruits by Id
var fruitsById = fruits.ToDictionary(k => k.Id, v => v); // Dictionary<int, Fruit>

// Generates a dictionary fruits by color
var fruitsByColor = fruits.GroupBy(g => g.Color).ToDictionary(k => k.Key, v => v.ToList()); // Dictionary of list of fruits by color

// Generates a dictionary of quantity of fruits by color
var fruitsByColor = fruits.GroupBy(g => g.Color).ToDictionary(k => k.Key, v => v.Sum(s => s.Quantity)); // Dictionary of sum of fruits by color