# Appendix D: Standard library index > Appendix D: where each part of the Alice standard library is described: Prelude methods on strings, arrays, hashes and numbers, the runtime types for concurrency and numerics, and the .NET base library. Canonical: https://alice-lang.org/documentation/learn/library-index/ [Documentation index](https://alice-lang.org/documentation/llms.txt) ยท [Complete book](https://alice-lang.org/llms-full.txt) Alice's library has three layers. This index tells you where to look. 1. **The Prelude**: Ruby-style methods on built-in types, such as `map`, `strip`, `tally`, `gcd`, and free functions such as `puts` and `format`. Always available. 2. **The Alice runtime**: types for concurrency, parallelism and numerics, such as `Channel(T)`, `Actor(T)`, `Par`, `Atomic` and `Tensor`. Always available. 3. **The .NET base library and NuGet**: everything else, by its .NET name ([chapter 14](https://alice-lang.org/documentation/learn/dotnet.md)). ## The Prelude | Type | Common methods | Reference | | ----------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- | | `String` | `size`, `strip`, `split`, `upcase`, `downcase`, `capitalize`, `includes?`, `starts_with?`, `sub`, `gsub`, `scan`, `match`, `match?`, `chars`, `lines`, `ljust`, `rjust`, `center`, `to_i`, `to_i?`, `to_f`, `reverse`, `tr`, `bytesize`, `camelcase`, `underscore` | [strings](https://alice-lang.org/documentation/library/strings.md), [chapter 5](https://alice-lang.org/documentation/learn/strings.md) | | `Char` | `upcase`, `downcase`, `letter?`, `digit?`, `whitespace?`, `ord`, `succ` | [strings](https://alice-lang.org/documentation/library/strings.md) | | `Array`, `List`, ranges | `each`, `each_with_index`, `map`, `select`, `reject`, `find`, `count`, `sum`, `min`, `max`, `minmax`, `sort`, `sort_by`, `uniq`, `reverse`, `first`, `last`, `take`, `drop`, `zip`, `flatten`, `group_by`, `partition`, `tally`, `each_slice`, `each_cons`, `reduce`, `inject`, `join`, `includes?`, `dup` | [collections](https://alice-lang.org/documentation/library/collections.md), [chapter 4](https://alice-lang.org/documentation/learn/collections.md) | | Arrays, data-parallel | `prefix_sum`, `segmented_sum`, `histogram`, `compact`, `scatter_add`, `permute`, `sort_by_key` | [chapter 11](https://alice-lang.org/documentation/learn/parallelism.md) | | `Hash` | `[]`, `fetch`, `key?`, `delete`, `each`, `keys`, `values`, `select`, `map`, `min_by`, `max_by`, `sort_by`, `transform_values`, `merge`, `dig`, `to_a`; `Hash(K, V).new(default)` | [hashes](https://alice-lang.org/documentation/library/hashes.md), [chapter 4](https://alice-lang.org/documentation/learn/collections.md) | | Integers and floats | `abs`, `even?`, `odd?`, `zero?`, `times`, `upto`, `downto`, `step`, `gcd`, `lcm`, `divmod`, `tdiv`, `remainder`, `clamp`, `between?`, `round`, `floor`, `ceil`, `sqrt`, `to_s(base)`, `to_i64`, `to_f` | [numbers](https://alice-lang.org/documentation/library/numbers.md), [chapter 3](https://alice-lang.org/documentation/learn/common-concepts.md) | | Enums | `to_i`, `Color.values`, `Color.names`, `Color.parse` | [chapter 7](https://alice-lang.org/documentation/learn/sum-types.md) | | Free functions | `puts`, `print`, `p`, `gets`, `format`, `rand`, `sleep`, `read_file`, `write_file`, `read_lines`, `file_exists?`, `env`, `to_json`, `parse_json`, `exit` | [files and JSON](https://alice-lang.org/documentation/library/io.md) | | Regular expressions | `/pattern/flags` literals, `MatchData` with `[]`, `pre_match`, `post_match`, `captures` | [regex](https://alice-lang.org/documentation/library/regex.md) | ## The Alice runtime | Type | Use | Chapter | | --------------------------------------- | ------------------------------------------------------------- | -------------------------------------------------------------------- | | `Channel(T)` | queues between threads | [15](https://alice-lang.org/documentation/learn/async.md) | | `Actor(T)`, `Actor(S, T)`, `Supervisor` | isolated state, messages, restarts | [15](https://alice-lang.org/documentation/learn/async.md) | | `Mutex(T)`, `Atomic` | guarded shared state | [10](https://alice-lang.org/documentation/learn/safety.md) | | `Par` | `For`, `Map`, `Sum` and other explicit parallel operations | [11](https://alice-lang.org/documentation/learn/parallelism.md) | | `SoA(T)` | columnar storage of `@[SoA]` record structs | [12](https://alice-lang.org/documentation/learn/performance.md) | | `Simd`, `AMath` | vector helpers and array math | [numerics](https://alice-lang.org/documentation/library/numerics.md) | | `Tensor`, `Nn` | tensor kernels: dot products, matrix multiply, softmax, norms | [tensors](https://alice-lang.org/documentation/guides/tensors.md) | | `CsrMatrix`, `SparseVector` | sparse linear algebra | [numerics](https://alice-lang.org/documentation/library/numerics.md) | ## The .NET base library Everything in .NET is available by name. The parts used in this book: | Namespace | For | | ---------------------------- | ----------------------------------------------------------- | | `System` | `Math`, `DateTime`, `Random`, `Guid`, `Convert`, exceptions | | `System.Text` | `StringBuilder`, encodings | | `System.Text.Json` | JSON serialization of records and classes | | `System.IO` | `File`, `Path`, `Directory`, streams | | `System.Collections.Generic` | `List`, `Dictionary`, `HashSet`, `Queue`, `Stack` | | `System.Linq` | `Where`, `Select`, `OrderBy` and other LINQ operators | | `System.Diagnostics` | `Stopwatch`, processes | | `System.Threading.Tasks` | `Task`, `Task.WhenAll`, `Task.Delay` | Microsoft's [.NET API browser](https://learn.microsoft.com/dotnet/api/) documents all of them. ## Continue reading - Previous: [Appendix C: Coming from Ruby, Crystal or C#](https://alice-lang.org/documentation/learn/from-ruby.md) - Next: [Appendix E: Coming in 1.0](https://alice-lang.org/documentation/learn/coming-in-1-0.md)