[Everyday C#] Phase E, PR 14a: Statements: collections + LINQ#54807
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BillWagner merged 9 commits intoJul 20, 2026
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Phase E, PR 14a. Adds two example-heavy Fundamentals concept articles under fundamentals/statements/ with compiling net10.0 snippet projects: - collections.md: arrays, List<T>, Dictionary<TKey,TValue>, adding/ removing/searching elements, collection expressions (C# 12), indexes and ranges (C# 8). - linq.md: query syntax, method syntax, filter/map/reduce/sort/group, lambda expressions, deferred vs eager evaluation. Adds Collections and LINQ entries to the Expressions and statements TOC node. Advanced topics (providers, IQueryable, expression trees, PLINQ, performance, custom collections/operators) are intentionally left to the Language Reference and LINQ sections and linked out. Closes dotnet#53556 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 7f9f7f68-82b8-43d2-a511-1a4f07138403
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Pull request overview
Adds two new “Everyday C#” Fundamentals concept articles under fundamentals/statements/ (Collections and LINQ), backed by new compiling snippet projects, and wires both pages into the C# TOC.
Changes:
- Adds new Fundamentals articles: Collections and LINQ queries.
- Adds new snippet projects (
collections-statementsandlinq-statements) that supply all referenced:::coderegions. - Updates
docs/csharp/toc.ymlto include the new pages under Fundamentals → Expressions and statements.
Reviewed changes
Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.
Show a summary per file
| File | Description |
|---|---|
| docs/csharp/toc.yml | Adds TOC entries for the new Collections and LINQ Fundamentals pages. |
| docs/csharp/fundamentals/statements/collections.md | New concept article introducing arrays, List<T>, dictionaries, collection expressions, and indexes/ranges with snippet-backed examples. |
| docs/csharp/fundamentals/statements/linq.md | New concept article introducing LINQ query/method syntax, common operators, grouping, and deferred execution with snippet-backed examples. |
| docs/csharp/fundamentals/statements/snippets/collections-statements/Program.cs | Snippet source for the Collections article :::code regions. |
| docs/csharp/fundamentals/statements/snippets/collections-statements/collections-statements.csproj | New net10.0 snippet project for Collections examples. |
| docs/csharp/fundamentals/statements/snippets/linq-statements/Program.cs | Snippet source for the LINQ article :::code regions. |
| docs/csharp/fundamentals/statements/snippets/linq-statements/linq-statements.csproj | New net10.0 snippet project for LINQ examples. |
Rename collections.md H1/title to "Arrays, lists, and dictionaries" to resolve the duplicate-H1 build warning, and collapse multiple-blank-line runs (MD012) in both statements articles. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 7f9f7f68-82b8-43d2-a511-1a4f07138403
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 7f9f7f68-82b8-43d2-a511-1a4f07138403
This is looking a little better.
BillWagner
marked this pull request as ready for review
July 16, 2026 19:45
adegeo
requested changes
Jul 17, 2026
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Very good! I wrote my comments as if talking to LLM, so they're curt.
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adegeo
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Jul 20, 2026
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Looks great! Two more minor things to fix.
…LINQ cross-reference wording Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
…ection' Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
adegeo
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Jul 21, 2026
Update the rules and comments based on everything learned in PR #54807
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Everyday C# — Phase E, PR 14a: Statements: collections + LINQ
Closes #53556
Adds two example-heavy Fundamentals concept articles under
fundamentals/statements/, each backed by a compilingnet10.0snippet project, and wires them into the TOC. Every code sample is included from an external snippet via:::coderegions and shows its result as a trailing// =>comment; the samples saturate the everyday feature set (collection expressions, file-scoped namespaces, nullable enabled, target-typednew).New articles
fundamentals/statements/collections.md— arrays,List<T>,Dictionary<TKey,TValue>; adding, removing, and searching elements; collection expressions (C# 12); indexes and ranges (C# 8) applied to collections. Introduces collection, element, sequence vs map, generic type / type safety, index, range, and collection expression at first use.fundamentals/statements/linq.md— query syntax and method (fluent) syntax; the functional trio filter / map / reduce mapped toWhere/Select/Aggregate·Sum·Count, plusOrderByandGroupBy; lambda (anonymous function) expressions in LINQ; deferred execution vs eager evaluation. Names LINQ providers as a first-class use and links out for provider-based queries.TOC
CollectionsandLINQadded under Fundamentals → Expressions and statements, afterIteration statements.Scope discipline — deliberately left out of Fundamentals (link-out targets)
No existing content was cut (both articles are new); the following advanced topics are intentionally kept out of Fundamentals and linked to their proper homes, per Goal 11 / Filter A:
collections.md→language-reference/builtin-types/arrays.md/collections.md→ multidimensional arrays, covariance, collection taxonomy are reference-level.collections.md→language-reference/operators/collection-expressions.md/member-access-operators.md→ conversion/spread rules and full[]/^/..operator rules are reference-level.collections.md→standard/collections/*→ choosing among specialized/concurrent/immutable collections and custom comparers fail universality.linq.md→linq/*(LINQ section) → joins, providers/IQueryable, deferred-execution mechanics, custom operators, XML/EF behavior are LINQ-focus material.linq.md→ PLINQ / expression trees / performance → parallel and advanced-representation material.Validation
net10.0; every// =>output verified by running the programs.#indexer-operator-anchor, and all<xref:...>UIDs verified to resolve; version claims (collection expressions → C# 12,^/..→ C# 8) confirmed.programming-guide/*link destinations (that area is slated for retirement).Opened as draft for review.
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