101 linq samples

101-linq-samples/docs/aggregates-1.md

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+# LINQ - Aggregators
+
+*Aggregator* methods return a single value calculated from all the elements in a sequence. the aggregator methods include `Count`, `Sum`, `Min`, `Max`, `Average`, and `Aggregate`.
+
+## Sum all numeric elements in a sequence
+
+This sample uses `Sum` to get the total of the numbers in an array.
+
+``` cs --region sum-syntax --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Sum a projection from a sequence
+
+This sample uses `Sum` to get the total number of characters of all words in the array.
+
+``` cs --region sum-of-projection --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Sum all elements that are members of a group
+
+This sample uses `Sum` to get the total units in stock for each product category.
+
+``` cs --region grouped-sum --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+**Next: [Aggregates-Min »](./aggregates-2.md) Previous:  [Aggregates »](./aggregates.md)**
+
+**[Home](../README.md)**

101-linq-samples/docs/aggregates-2.md

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+# LINQ - Aggregators
+
+*Aggregator* methods return a single value calculated from all the elements in a sequence. the aggregator methods include `Count`, `Sum`, `Min`, `Max`, `Average`, and `Aggregate`.
+
+## Find the minimum of a sequence of elements
+
+This sample uses `Min` to get the lowest number in an array.
+
+``` cs --region min-syntax --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Find the minimum of a projection
+
+This sample uses `Min` to get the length of the shortest word in an array.
+
+``` cs --region min-projection --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Find the minimum in each group
+
+This sample uses `Min` to get the cheapest price among each category's products.
+
+``` cs --region min-grouped --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Find all elements matching the minimum
+
+This sample uses `Min` to get the products with the cheapest price in each category.
+
+``` cs --region min-each-group --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+**Next: [Aggregates-Max »](./aggregates-3.md) Previous:  [Aggregates-Sum »](./aggregates-1.md)**
+
+**[Home](../README.md)**

101-linq-samples/docs/aggregates-3.md

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+# LINQ - Aggregators
+
+*Aggregator* methods return a single value calculated from all the elements in a sequence. the aggregator methods include `Count`, `Sum`, `Min`, `Max`, `Average`, and `Aggregate`.
+
+## Find the maximun of a sequence of elements
+
+This sample uses `Max` to get the highest number in an array.
+
+``` cs --region max-syntax --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Find the maximum of a projection
+
+This sample uses `Max` to get the length of the longest word in an array.
+
+``` cs --region max-projection --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Find the maximum in each group
+
+This sample uses `Max` to get the most expensive price among each category's products.
+
+``` cs --region max-grouped --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Find all elements matching the maximum
+
+This sample uses `Max` to get the products with the most expensive price in each category.
+
+``` cs --region max-each-group --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+**Next: [Aggregates-Average »](./aggregates-4.md) Previous:  [Aggregates-Min »](./aggregates-2.md)**
+
+**[Home](../README.md)**

101-linq-samples/docs/aggregates-4.md

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+# LINQ - Aggregators
+
+*Aggregator* methods return a single value calculated from all the elements in a sequence. the aggregator methods include `Count`, `Sum`, `Min`, `Max`, `Average`, and `Aggregate`.
+
+## Find the average of a sequence of elements
+
+This sample uses `Average` to get the average of all numbers in an array.
+
+``` cs --region average-syntax --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Find the average of a projection
+
+This sample uses `Average` to get the average length of the words in the array.
+
+``` cs --region average-projection --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Find the average in each group
+
+This sample uses `Average` to get the average price of each category's products.
+
+``` cs --region average-grouped --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Compute an aggregate value from all elements of a sequence
+
+This sample uses `Aggregate` to create a running product on the array that calculates the total product of all elements.
+
+``` cs --region aggregate-syntax --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Compute an aggregate value from a seed value and all elements of a sequence
+
+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.
+
+``` cs --region aggregate-seeded --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+**Next: [Sequence operations »](./sequence-operations.md) Previous:  [Aggregates-Min »](./aggregates-2.md)**
+
+**[Home](../README.md)**

101-linq-samples/docs/aggregates.md

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+# LINQ - Aggregators
+
+*Aggregator* methods return a single value calculated from all the elements in a sequence. the aggregator methods include `Count`, `Sum`, `Min`, `Max`, `Average`, and `Aggregate`.
+
+## Count all elements in a sequence
+
+This sample uses `Count` to get the number of unique factors of 300.
+
+``` cs --region count-syntax --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Count all elements matching a condition
+
+This sample uses `Count` to get the number of odd ints in the array.
+
+
+``` cs --region count-conditional --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Count all elements nested in a query
+
+This sample uses `Count` to return a list of customers and how many orders each has.
+
+``` cs --region nested-count --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Count all elements that are members of a group
+
+This sample uses `Count` to return a list of categories and how many products each has.
+
+``` cs --region grouped-count --source-file ../src/AggregateOperators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+**Next: [Aggregates-Sum »](./aggregates-1.md) Previous:  [Quantifiers »](./generators.md)**
+
+**[Home](../README.md)**

101-linq-samples/docs/conversions.md

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+# LINQ - Conversion Operators
+
+The methods `ToArray`, `ToArray`, `ToDictionary`, and `OfType` provide ways to convert LINQ results to collections.
+
+## Convert to an array
+
+This sample uses `ToArray` to immediately evaluate a sequence into an array.
+
+``` cs --region convert-to-array --source-file ../src/Conversions.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Convert to a list
+
+This sample uses `ToList` to immediately evaluate a sequence into a `List<T>`.
+
+``` cs --region convert-to-list --source-file ../src/Conversions.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Convert to a dictionary
+
+This sample uses `ToDictionary` to immediately evaluate a sequence and a related key expression into a dictionary.
+
+``` cs --region convert-to-dictionary --source-file ../src/Conversions.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Convert elements that match a type
+
+This sample uses `OfType` to return only the elements of the array that are of type `double`.
+
+``` cs --region convert-to-type --source-file ../src/Conversions.cs --project ../src/Try101LinqSamples.csproj
+```
+
+**Next: [Element operations &raquo;](./elements.md) Previous:  [Intersect and except set operations &raquo;](./sets-2.md)**
+
+**[Home](../README.md)**

101-linq-samples/docs/elements.md

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+# LINQ - Element Operators
+
+The methods `First`, `FirstOrDefault`, and `ElementAt` provide ways to select a single element by position.
+
+## Find the first element
+
+This sample uses `First` to return the first matching element as a `Product`, instead of as a sequence containing a `Product`.
+
+``` cs --region first-element --source-file ../src/ElementOperations.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Find the first matching element
+
+This sample uses `First` to find the first element in the array that starts with 'o'.
+
+``` cs --region first-matching-element --source-file ../src/ElementOperations.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## First element of a possibly empty sequence
+
+This sample uses `FirstOrDefault` to try to return the first element of the sequence, unless there are no elements, in which case the default value for that type is returned.
+
+``` cs --region first-or-default --source-file ../src/ElementOperations.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## First matching element or default
+
+This sample uses `FirstOrDefault` to return the first product whose `ProductID` is `789` as a single `Product` object, unless there is no match, in which case `null` is returned.
+
+``` cs --region first-matching-or-default --source-file ../src/ElementOperations.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Find element at position
+
+This sample uses `ElementAt` to retrieve the second number greater than 5 from an array.
+
+``` cs --region element-at --source-file ../src/ElementOperations.cs --project ../src/Try101LinqSamples.csproj
+```
+
+**Next: [Generate sequences »](./generators.md) Previous:  [Conversion operations »](./conversions.md)**
+
+**[Home](../README.md)**

101-linq-samples/docs/generators.md

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+# LINQ - Generate elements
+
+The methods `Range` and `Repeat` create sequences of integers. These can be the source sequences of queries.
+
+## Create a range of numbers
+
+This sample uses `First` to return the first matching element as a `Product`, instead of as a sequence containing a `Product`.
+
+``` cs --region generate-range --source-file ../src/Generators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Repeat the same number
+
+This sample uses `First` to find the first element in the array that starts with 'o'.
+
+``` cs --region generate-repeat --source-file ../src/Generators.cs --project ../src/Try101LinqSamples.csproj
+```
+
+**Next: [Quantifying operations »](./quantifiers.md) Previous:  [Conversion operations »](./conversions.md)**
+
+**[Home](../README.md)**

101-linq-samples/docs/groupings-2.md

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+# LINQ - Grouping Operators with custom comparer
+
+The `group by` and `into` can use custom comparers to separate groups.
+
+These samples use the following custom comparer. It compares two strings to see if they are anagrams. (Anagrams are pairs of words formed from the same letters.)
+
+``` cs --region anagram-comparer --session groupby-custom-comparer --source-file ../src/Groupings.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Groupby with a custom comparer
+
+
+``` cs --region groupby-custom-comparer --session groupby-custom-comparer --source-file ../src/Groupings.cs --project ../src/Try101LinqSamples.csproj
+```
+
+**Next: [Nested groupings with a custom comparer »](./groupings-3.md) Previous: [Groupings «](./groupings.md)**
+
+**[Home](../README.md)**

101-linq-samples/docs/groupings-3.md

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+# LINQ - Nested Grouping Operators with custom comparer
+
+The `group by` and `into` can use custom comparers to separate groups. These queries can be nested.
+
+These samples use the following custom comparer. It compares two strings to see if they are anagrams. (Anagrams are pairs of words formed from the same letters.)
+
+``` cs --region anagram-comparer --session nested-groupby-custom --source-file ../src/Groupings.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Groupby with a custom comparer
+
+
+``` cs --region nested-groupby-custom --session nested-groupby-custom --source-file ../src/Groupings.cs --project ../src/Try101LinqSamples.csproj
+```
+
+**Next: [Set operations »](./sets.md) Previous: [Groupings with a custom comparer «](./orderings-2.md)**
+
+**[Home](../README.md)**

101-linq-samples/docs/groupings.md

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+# LINQ - Grouping Operators
+
+The `group by` and `into` keywords provide grouping constructs to organize elements of the input sequence into buckets.
+
+## Group by into buckets
+
+This sample demonstrates the use of `group by` and `into` to create buckets based on the remainder of an integer when dividing it by 5.
+
+``` cs --region groupby-syntax --source-file ../src/Groupings.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Groupby using a property
+
+This sample uses `group by` to partition a list of words by their first letter.
+
+``` cs --region groupby-property --source-file ../src/Groupings.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Grouping using a key property
+
+This sample uses `group by` to partition a list of products by category.
+
+``` cs --region groupby-category --source-file ../src/Groupings.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Nested group by queries
+
+This sample demonstrates the use of `group by` and `into` nested buckets of orders by customer, year, and month. The result 
+
+``` cs --region nested-groupby --source-file ../src/Groupings.cs --project ../src/Try101LinqSamples.csproj
+```
+
+**Next: [Grouping with a custom comparer »](./groupings-2.md) Previous: [Nested custom comparisons «](./orderings-5.md)**
+
+**[Home](../README.md)**

101-linq-samples/docs/join-operators.md

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+# LINQ - Join operations
+
+Learn to use cross `join`, group `join`, and left outer `join` operations in LINQ queries
+
+## Cross join
+
+This sample shows how to efficiently join elements of two sequences based on equality between key expressions over the two.
+
+``` cs --region cross-join --source-file ../src/JoinOperations.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Group join
+
+Using a group `join` you can get all the products that match a given category bundled as a sequence.
+
+``` cs --region group-join --source-file ../src/JoinOperations.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Cross join with group join
+
+The group `join` operator is more general than `join`, as this slightly more verbose version of the cross `join` sample shows.
+
+``` cs --region cross-group-join --source-file ../src/JoinOperations.cs --project ../src/Try101LinqSamples.csproj
+```
+
+## Left outer join using group join
+
+A so-called outer join can be expressed with a `group join`. A left outer join is like a cross join, except that all the left hand side elements get included at least once, even if they don't match any right hand side elements. Note how `Vegetables` shows up in the output even though it has no matching products.
+
+``` cs --region left-outer-join --source-file ../src/JoinOperations.cs --project ../src/Try101LinqSamples.csproj
+```
+
+**Previous:  [Query execution »](./query-execution.md)**
+
+**[Home](../README.md)**