Session 6: LINQ and Extension Methods¶

var ourDeck = TheDeck.Shuffle().Shuffle();

var hand1 = new List<Card>();
var hand2 = new List<Card>();
var hand3 = new List<Card>();
hand1.Add(ourDeck.Skip(1).First());
hand2.Add(ourDeck.Skip(2).First());
hand3.Add(ourDeck.Skip(3).First());
hand1.Add(ourDeck.Skip(4).First());
hand2.Add(ourDeck.Skip(5).First());
hand3.Add(ourDeck.Skip(6).First());

display("Hand 1");
display(hand1);
display("Hand 2");
display(hand2);
display("Hand 3");
display(hand3);

// Burn a card and deal the next 3 cards called 'the flop'
display("The Flop");
display(ourDeck.Skip(8).Take(3));
    
// Burn a card and take one card called 'the turn'
display("The Turn");
display(ourDeck.Skip(12).First());

// Burn a card and take the final card called 'the river'
display("The River");
display(ourDeck.Skip(14).First());

// The simplest query
var outValues = from card in TheDeck // the required collection we are querying
                select card;         // the values to be returned

outValues

var results = from card in TheDeck
              where card.Suit == "h"    // Return just the Hearts
              orderby card.RankValue descending
              select card;
              
results

var results = from card in TheDeck
              where card.Suit == "h" && card.RankValue > 10
              select card.Rank;
              
results

class Person
{
    public string Name { get; set; }
}

class Pet
{
    public string Name { get; set; }
    public Person Owner { get; set; }
}

    Person magnus = new Person { Name = "Hedlund, Magnus" };
    Person terry = new Person { Name = "Adams, Terry" };
    Person charlotte = new Person { Name = "Weiss, Charlotte" };

    // Declare the set of 4 pets and their owners
    Pet barley = new Pet { Name = "Barley", Owner = terry };
    Pet boots = new Pet { Name = "Boots", Owner = terry };
    Pet whiskers = new Pet { Name = "Whiskers", Owner = charlotte };
    Pet daisy = new Pet { Name = "Daisy", Owner = magnus };

    List<Person> people = new List<Person> { magnus, terry, charlotte };
    List<Pet> pets = new List<Pet> { barley, boots, whiskers, daisy };

    // Create a list of Person-Pet pairs where
    // each element is an anonymous type that contains a
    // Pet's name and the name of the Person that owns the Pet.
    var query =
        people.Join(pets,                 // Join the People and Pets collections
                    person => person,     // We will match the Person object
                    pet => pet.Owner,     // with the Owner property in the Pet record
                    (person, pet) =>      // The combined output of Person and Pet
                                          // is an object with OwnerName and the Pet's Name
                        new { OwnerName = person.Name, Pet = pet.Name });

    foreach (var obj in query)
    {
        display(string.Format("{0} - {1}",
            obj.OwnerName,
            obj.Pet));
    }

var results = from card in TheDeck
              group card by card.Suit;

display(results.GetType());
results

var results = from card in TheDeck
              group card by card.Suit into suit
              select new {TheSuit=suit.Key, suit};

display(results.GetType());
results

var results = from card in TheDeck
              group card by card.RankValue > 10 into facecards
              select new {TheSuit=facecards.Key, facecards};

results

var results = from card in TheDeck
              where card.RankValue > 10
              group card by card.Rank into facecards
              select new {Face=facecards.Key, facecards};

results

#r "nuget:LinqToCsv"
using LINQtoCSV;

class MyDataRow { 
    [CsvColumn(Name = "Year", FieldIndex = 1)]
    public int Year {get; set;}
    [CsvColumn(Name = "Number of tropical storms", FieldIndex = 2)]
    public byte TropicalStormCount { get; set;}
    [CsvColumn(Name = "Number of hurricanes", FieldIndex = 3)]
    public byte HurricaneCount { get; set;}
    [CsvColumn(Name = "Number of major hurricanes", FieldIndex = 4)]
    public byte MajorHurricaneCount { get; set;}
    
    // Accumulated Cyclone Energy
    [CsvColumn(Name = "ACE", FieldIndex = 5)]
    public decimal ACE { get; set; }
    
    [CsvColumn(Name = "Deaths", FieldIndex = 6)]
    public int Deaths { get; set; }

    [CsvColumn(Name="Strongest storm", FieldIndex = 7)]
    public string StrongestStorm { get; set; }
    
    [CsvColumn(Name = "Damage USD", FieldIndex = 8)]
    public string DamageUSD { get; set; }

    [CsvColumn(Name = "Retired names", FieldIndex = 9)]
    public string RetiredNames { get; set; }

    [CsvColumn(Name = "Notes", FieldIndex = 10)]
    public string Notes { get; set; }

    
}
var inputFileDescription = new CsvFileDescription
{
    SeparatorChar = ',', 
    FirstLineHasColumnNames = true
};
var context = new CsvContext();
var hurricanes = context.Read<MyDataRow>("data/atlantic_hurricanes.csv", inputFileDescription);
display(hurricanes.OrderByDescending(h => h.Year).Take(10).Select(h => new {h.Year, h.TropicalStormCount, h.HurricaneCount, h.StrongestStorm}));

var results = from storm in hurricanes
              orderby storm.DamageUSD descending
              where storm.HurricaneCount >= 10
              select new {storm.Year, storm.HurricaneCount, storm.ACE, storm.StrongestStorm, storm.DamageUSD};

results