Count - Simple

This sample uses Count to get the number of unique prime factors of 300.

Code:

            public void Linq73()
            {
                int[] primeFactorsOf300 = { 2, 2, 3, 5, 5 };

                int uniqueFactors = primeFactorsOf300.Distinct().Count();

                Log.WriteLine("There are {0} unique prime factors of 300.", uniqueFactors);
            }

Result:

Count - Conditional

This sample uses Count to get the number of odd ints in the array.

Code:

            public void Linq74()
            {
                int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };

                int oddNumbers = numbers.Count(n => n % 2 == 1);

                Log.WriteLine("There are {0} odd numbers in the list.", oddNumbers);
            }

Result:

Count - Nested

This sample uses Count to return a list of customers and how many orders each has.

Code:

            public void Linq76()
            {
                List customers = GetCustomerList();

                var orderCounts = customers.Select(cust => new {cust.CustomerID, OrderCount = cust.Orders.Count()});

                ObjectDumper.Write(orderCounts);
            }

Result:

CustomerID=ALFKI        OrderCount=6
CustomerID=ANATR        OrderCount=4
CustomerID=ANTON        OrderCount=7
CustomerID=AROUT        OrderCount=13
CustomerID=BERGS        OrderCount=18
CustomerID=BLAUS        OrderCount=7
CustomerID=BLONP        OrderCount=11
CustomerID=BOLID        OrderCount=3
CustomerID=BONAP        OrderCount=17
CustomerID=BOTTM        OrderCount=14
CustomerID=BSBEV        OrderCount=10
CustomerID=CACTU        OrderCount=6
CustomerID=CENTC        OrderCount=1
CustomerID=CHOPS        OrderCount=8
CustomerID=COMMI        OrderCount=5
CustomerID=CONSH        OrderCount=3
CustomerID=DRACD        OrderCount=6
CustomerID=DUMON        OrderCount=4
CustomerID=EASTC        OrderCount=8
CustomerID=ERNSH        OrderCount=30
CustomerID=FAMIA        OrderCount=7
CustomerID=FISSA        OrderCount=0
CustomerID=FOLIG        OrderCount=5
CustomerID=FOLKO        OrderCount=19
CustomerID=FRANK        OrderCount=15
CustomerID=FRANR        OrderCount=3
CustomerID=FRANS        OrderCount=6
CustomerID=FURIB        OrderCount=8
CustomerID=GALED        OrderCount=5
CustomerID=GODOS        OrderCount=10
CustomerID=GOURL        OrderCount=9
CustomerID=GREAL        OrderCount=11
CustomerID=GROSR        OrderCount=2
CustomerID=HANAR        OrderCount=14
CustomerID=HILAA        OrderCount=18
CustomerID=HUNGC        OrderCount=5
CustomerID=HUNGO        OrderCount=19
CustomerID=ISLAT        OrderCount=10
CustomerID=KOENE        OrderCount=14
CustomerID=LACOR        OrderCount=4
CustomerID=LAMAI        OrderCount=14
CustomerID=LAUGB        OrderCount=3
CustomerID=LAZYK        OrderCount=2
CustomerID=LEHMS        OrderCount=15
CustomerID=LETSS        OrderCount=4
CustomerID=LILAS        OrderCount=14
CustomerID=LINOD        OrderCount=12
CustomerID=LONEP        OrderCount=8
CustomerID=MAGAA        OrderCount=10
CustomerID=MAISD        OrderCount=7
CustomerID=MEREP        OrderCount=13
CustomerID=MORGK        OrderCount=5
CustomerID=NORTS        OrderCount=3
CustomerID=OCEAN        OrderCount=5
CustomerID=OLDWO        OrderCount=10
CustomerID=OTTIK        OrderCount=9
CustomerID=PARIS        OrderCount=0
CustomerID=PERIC        OrderCount=6
CustomerID=PICCO        OrderCount=10
CustomerID=PRINI        OrderCount=6
CustomerID=QUEDE        OrderCount=9
CustomerID=QUEEN        OrderCount=13
CustomerID=QUICK        OrderCount=28
CustomerID=RANCH        OrderCount=5
CustomerID=RATTC        OrderCount=18
CustomerID=REGGC        OrderCount=12
CustomerID=RICAR        OrderCount=11
CustomerID=RICSU        OrderCount=10
CustomerID=ROMEY        OrderCount=5
CustomerID=SANTG        OrderCount=6
CustomerID=SAVEA        OrderCount=31
CustomerID=SEVES        OrderCount=9
CustomerID=SIMOB        OrderCount=7
CustomerID=SPECD        OrderCount=4
CustomerID=SPLIR        OrderCount=9
CustomerID=SUPRD        OrderCount=12
CustomerID=THEBI        OrderCount=4
CustomerID=THECR        OrderCount=3
CustomerID=TOMSP        OrderCount=5
CustomerID=TORTU        OrderCount=10
CustomerID=TRADH        OrderCount=7
CustomerID=TRAIH        OrderCount=3
CustomerID=VAFFE        OrderCount=11
CustomerID=VICTE        OrderCount=10
CustomerID=VINET        OrderCount=4
CustomerID=WANDK        OrderCount=10
CustomerID=WARTH        OrderCount=15
CustomerID=WELLI        OrderCount=9
CustomerID=WHITC        OrderCount=14
CustomerID=WILMK        OrderCount=8
CustomerID=WOLZA        OrderCount=7

Count - Grouped

This sample uses Count to return a list of categories and how many products each has.

Code:

            public void Linq77()
            {
                List products = GetProductList();

                var categoryCounts = products.GroupBy(prod => prod.Category).
                    Select(prodGroup => new {Category = prodGroup.Key, ProductCount = prodGroup.Count()});

                ObjectDumper.Write(categoryCounts);
            }

Result:

Sum - Simple

This sample uses Sum to add all the numbers in an array.

Code:

            public void Linq78()
            {
                int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };

                double numSum = numbers.Sum();

                Log.WriteLine("The sum of the numbers is {0}.", numSum);
            }

Result:

Sum - Projection

This sample uses Sum to get the total number of characters of all words in the array.

Code:

            public void Linq79()
            {
                string[] words = { "cherry", "apple", "blueberry" };

                double totalChars = words.Sum(w => w.Length);

                Log.WriteLine("There are a total of {0} characters in these words.", totalChars);
            }

Result:

Sum - Grouped

This sample uses Sum to get the total units in stock for each product category.

Code:

            public void Linq80()
            {
                List products = GetProductList();

                var categories = products.GroupBy(prod => prod.Category).
                    Select(prodGroup => new {Category = prodGroup.Key, TotalUnitsInStock = prodGroup.Sum(p => p.UnitsInStock)});

                ObjectDumper.Write(categories);
            }

Result:

Min - Simple

This sample uses Min to get the lowest number in an array.

Code:

            public void Linq81()
            {
                int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };

                int minNum = numbers.Min();

                Log.WriteLine("The minimum number is {0}.", minNum);
            }

Result:

Min - Projection

This sample uses Min to get the length of the shortest word in an array.

Code:

            public void Linq82()
            {
                string[] words = { "cherry", "apple", "blueberry" };

                int shortestWord = words.Min(w => w.Length);

                Log.WriteLine("The shortest word is {0} characters long.", shortestWord);
            }

Result:

Min - Grouped

This sample uses Min to get the cheapest price among each category's products.

Code:

            public void Linq83()
            {
                List products = GetProductList();

                var categories = products.GroupBy(prod => prod.Category).Select(prodGroup => new {Category = prodGroup.Key, CheapestPrice = prodGroup.Min(p => p.UnitPrice)});

                ObjectDumper.Write(categories);
            }

Result:

Min - Elements

This sample uses Min to get the products with the lowest price in each category.

Code:

            public void Linq84()
            {
                List products = GetProductList();

                var categories = products.GroupBy(prod => prod.Category).
                    Select(prodGroup => new {prodGroup, minPrice = prodGroup.Min(p => p.UnitPrice)}).
                    Select(@t => new {
                        Category = @t.prodGroup.Key, 
                        CheapestProducts = @t.prodGroup.Where(p => p.UnitPrice == @t.minPrice)});

                ObjectDumper.Write(categories, 1);
            }

Result:

Category=Beverages      CheapestProducts=...
  CheapestProducts: ProductID=24  ProductName=Guaraná Fantástica  Category=Beverages      UnitPrice=4,5000        UnitsInStock=20
Category=Condiments     CheapestProducts=...
  CheapestProducts: ProductID=3   ProductName=Aniseed Syrup       Category=Condiments     UnitPrice=10,0000       UnitsInStock=13
Category=Produce        CheapestProducts=...
  CheapestProducts: ProductID=74  ProductName=Longlife Tofu       Category=Produce        UnitPrice=10,0000       UnitsInStock=4
Category=Meat/Poultry   CheapestProducts=...
  CheapestProducts: ProductID=54  ProductName=Tourtière   Category=Meat/Poultry   UnitPrice=7,4500        UnitsInStock=21
Category=Seafood        CheapestProducts=...
  CheapestProducts: ProductID=13  ProductName=Konbu       Category=Seafood        UnitPrice=6,0000        UnitsInStock=24
Category=Dairy Products         CheapestProducts=...
  CheapestProducts: ProductID=33  ProductName=Geitost     Category=Dairy Products         UnitPrice=2,5000        UnitsInStock=112
Category=Confections    CheapestProducts=...
  CheapestProducts: ProductID=19  ProductName=Teatime Chocolate Biscuits  Category=Confections    UnitPrice=9,2000        UnitsInStock=25
Category=Grains/Cereals         CheapestProducts=...
  CheapestProducts: ProductID=52  ProductName=Filo Mix    Category=Grains/Cereals         UnitPrice=7,0000        UnitsInStock=38

Max - Simple

This sample uses Max to get the highest number in an array. Note that the method returns a single value.

Code:

            public void Linq85()
            {
                int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };

                int maxNum = numbers.Max();

                Log.WriteLine("The maximum number is {0}.", maxNum);
            }

Result:

Max - Projection

This sample uses Max to get the length of the longest word in an array.

Code:

            public void Linq86()
            {
                string[] words = { "cherry", "apple", "blueberry" };

                int longestLength = words.Max(w => w.Length);

                Log.WriteLine("The longest word is {0} characters long.", longestLength);
            }

Result:

Max - Grouped

This sample uses Max to get the most expensive price among each category's products.

Code:

            public void Linq87()
            {
                List products = GetProductList();

                var categories = products.GroupBy(prod => prod.Category)
                    .Select(prodGroup => new {Category = prodGroup.Key, MostExpensivePrice = prodGroup.Max(p => p.UnitPrice)});

                ObjectDumper.Write(categories);
            }

Result:

Max - Elements

This sample uses Max to get the products with the most expensive price in each category.

Code:

            public void Linq88()
            {
                List products = GetProductList();

                var categories = products.GroupBy(prod => prod.Category)
                    .Select(prodGroup => new {
                        prodGroup, 
                        maxPrice = prodGroup.Max(p => p.UnitPrice)}).Select(@t => new {
                            Category = @t.prodGroup.Key, 
                            MostExpensiveProducts = @t.prodGroup.Where(p => p.UnitPrice == @t.maxPrice)});

                ObjectDumper.Write(categories, 1);
            }

Result:

Category=Beverages      MostExpensiveProducts=...
  MostExpensiveProducts: ProductID=38     ProductName=Côte de Blaye       Category=Beverages      UnitPrice=263,5000      UnitsInStock=17
Category=Condiments     MostExpensiveProducts=...
  MostExpensiveProducts: ProductID=63     ProductName=Vegie-spread        Category=Condiments     UnitPrice=43,9000       UnitsInStock=24
Category=Produce        MostExpensiveProducts=...
  MostExpensiveProducts: ProductID=51     ProductName=Manjimup Dried Apples       Category=Produce        UnitPrice=53,0000       UnitsInStock=20
Category=Meat/Poultry   MostExpensiveProducts=...
  MostExpensiveProducts: ProductID=29     ProductName=Thüringer Rostbratwurst     Category=Meat/Poultry   UnitPrice=123,7900      UnitsInStock=0
Category=Seafood        MostExpensiveProducts=...
  MostExpensiveProducts: ProductID=18     ProductName=Carnarvon Tigers    Category=Seafood        UnitPrice=62,5000       UnitsInStock=42
Category=Dairy Products         MostExpensiveProducts=...
  MostExpensiveProducts: ProductID=59     ProductName=Raclette Courdavault        Category=Dairy Products         UnitPrice=55,0000       UnitsInStock=79
Category=Confections    MostExpensiveProducts=...
  MostExpensiveProducts: ProductID=20     ProductName=Sir Rodney's Marmalade      Category=Confections    UnitPrice=81,0000       UnitsInStock=40
Category=Grains/Cereals         MostExpensiveProducts=...
  MostExpensiveProducts: ProductID=56     ProductName=Gnocchi di nonna Alice      Category=Grains/Cereals         UnitPrice=38,0000       UnitsInStock=21

Average - Simple

This sample uses Average to get the average of all numbers in an array.

Code:

            public void Linq89()
            {
                int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };

                double averageNum = numbers.Average();

                Log.WriteLine("The average number is {0}.", averageNum);
            }

Result:

Average - Projection

This sample uses Average to get the average length of the words in the array.

Code:

            public void Linq90()
            {
                string[] words = { "cherry", "apple", "blueberry" };

                double averageLength = words.Average(w => w.Length);

                Log.WriteLine("The average word length is {0} characters.", averageLength);
            }

Result:

Average - Grouped

This sample uses Average to get the average price of each category's products.

Code:

            public void Linq91()
            {
                List products = GetProductList();

                var categories = products.GroupBy(prod => prod.Category).
                    Select(prodGroup => new {Category = prodGroup.Key, AveragePrice = prodGroup.Average(p => p.UnitPrice)});

                ObjectDumper.Write(categories);
            }

Result:

Aggregate - Simple

This sample uses Aggregate to create a running product on the array that calculates the total product of all elements.

Code:

            public void Linq92()
            {
                double[] doubles = { 1.7, 2.3, 1.9, 4.1, 2.9 };

                double product = doubles.Aggregate((runningProduct, nextFactor) => runningProduct * nextFactor);

                Log.WriteLine("Total product of all numbers: {0}", product);
            }

Result:

Aggregate - Seed

This sample uses Aggregate to create a running account balance that subtracts each withdrawal from the initial balance of 100, as long as the balance never drops below 0.

Code:

            public void Linq93()
            {
                double startBalance = 100.0;

                int[] attemptedWithdrawals = { 20, 10, 40, 50, 10, 70, 30 };

                double endBalance =
                    attemptedWithdrawals.Aggregate(startBalance,
                        (balance, nextWithdrawal) =>
                            ((nextWithdrawal <= balance) ? (balance - nextWithdrawal) : balance));

                Log.WriteLine("Ending balance: {0}", endBalance);
            }

Aggregate Operators

Count - Simple

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Count - Conditional

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Count - Nested

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Count - Grouped

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Sum - Simple

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Sum - Projection

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Sum - Grouped

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Min - Simple

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Min - Projection

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Min - Grouped

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Min - Elements

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Max - Simple

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Max - Projection

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Max - Grouped

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Max - Elements

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Average - Simple

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Average - Projection

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Average - Grouped

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Aggregate - Simple

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Aggregate - Seed

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