Struct
A struct is a composite data type or structure that groups related fields or values into a single unit.
Go in Practice, Second Edition
A struct is a composite Go type that groups named or anonymous fields into a single value.
- How it is used
- Represents known application data, including configuration and JSON responses, while providing a type to which behavior can be attached.
- How deep it goes
- Works through fields, anonymous structs, tags, methods, JSON mapping, and runtime inspection rather than stopping at a syntax definition.
- Examples
- Uses an inline struct, JSON-encoded data, a configuration file, interface-implementing types, and a recursive field walker.
- What you can do after
- Build it from scratch to model known data, map JSON fields, and add methods; diagnose/debug with reflection when fields need runtime inspection.
Kafka Streams in Action, Second Edition
Struct is a Kafka Connect data structure that stores record field values together with schema-defined type information.
- How it is used
- Carries schema-backed Kafka Connect record values and models nested ksqlDB event fields.
- How deep it goes
- Explains construction, field copying, schema caching, nested declarations, and dereferencing without detailing serialization internals.
- Examples
- Uses stock-ticker SourceRecords, selected-field transformations, and a nested school-event JSON schema.
- What you can do after
- Build it from scratch as a schema-backed Connect value or declare and query nested ksqlDB fields.
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Elixir in Action, Third Edition
An Elixir struct is a map-like data structure associated with a module and containing a defined set of fields.
- How it is used
- Uses structs to define precise data abstractions, distinguish instances from plain maps, and organize module functions around them.
- How deep it goes
- Explains definition, construction, access, pattern matching, updating, internal map behavior, and selected failure modes.
- Examples
- Demonstrates Fraction arithmetic and a TodoList that assigns incremental IDs while storing entries by ID.
- What you can do after
- Builds module-backed data abstractions with defined fields, pattern-matched operations, and immutable updates.
Modern C
- How it is used
- Groups related, named values when array positions would be ambiguous or the values may have different types.
- How deep it goes
- Works through type declarations, designated initialization, member access, nested structures, and pointer access; defers the broader treatment of pointers.
- Examples
- Uses named bird fields, calendar fields in `struct tm`, and a function that updates a day-of-year field.
- What you can do after
- Build it from scratch: declare a structure, initialize named members, access them with `.`, and use `->` through a structure pointer.
Refactoring to Rust
A struct is a Rust composite type that groups named fields into a single logical value and can have associated functionality.
- How it is used
- Groups related fields into values passed to functions or populated from JSON and XML.
- How deep it goes
- Defines named fields and initialization, then demonstrates moves and derived deserialization; does not develop struct methods.
- Examples
- Uses an artwork value, a JSON name-and-number record, and nested XML search results.
- What you can do after
- Build it from scratch as a named-field value, and apply it via Serde to parse JSON or XML.
DuckDB in Action
A struct is a named-field data structure in which each field has a defined data type.
- How it is used
- Uses structs to represent nested records and simplify complex-data preparation in analytical SQL workflows.
- How deep it goes
- Explains definitions, inferred schemas, unnesting, whole-STRUCT casts, field expansion, and aggregation, without detailing internal storage.
- Examples
- Demonstrates Premier League shot JSON, inferred STRUCT arrays, explicit casts, flattened views, and expected-goals aggregation.
- What you can do after
- Apply structs in DuckDB SQL to inspect, normalize, flatten, and aggregate nested JSON records.
Learn Rust in a Month of Lunches
- How it is used
- Groups related values into custom Rust types, while distinguishing that job from an enum’s selection among choices.
- How deep it goes
- Works through unit, tuple, and named forms, complete initialization, field shorthand, and methods without addressing memory layout.
- Examples
- Uses a country’s fields, positional color values, an animal with methods, and article data parsed from JSON.
- What you can do after
- Build it from scratch with struct declarations and complete initializers, then attach methods through an impl block.
Julia as a Second Language
The struct keyword is Julia syntax for defining a composite type.
- How it is used
- Defines composite types that group application data, from game characters to rocket components.
- How deep it goes
- Works through typed fields, instance creation, field access, mutability, and fixed-field performance implications.
- Examples
- Uses an archer’s typed fields and instances, a warrior type hierarchy, and a rocket assembled from component objects.
- What you can do after
- Build it from scratch: define typed composite objects, instantiate them, access their fields, and choose mutability when fields must change.
Go in Action, Second Edition
The struct keyword introduces a Go struct type declaration.
- How it is used
- Groups related values into reusable domain types, including measurements in a recipe application.
- How deep it goes
- Works through declarations, fields, literals, access, and visibility, then connects structs to larger models without detailing their runtime representation.
- Examples
- Uses a reusable person declaration and recipe measurements, then assembles ingredients and steps into a scalable recipe.
- What you can do after
- Build it from scratch: define and initialize a named struct, access its fields, and use it to represent related domain data.
Modern C, Third Edition
The struct keyword introduces or refers to a C structure type through its structure tag.
- How it is used
- Organizes related values under named fields when array positions are ambiguous or member types differ.
- How deep it goes
- Explains declarations, objects, member access, heterogeneous fields, nesting, and visibility, while deferring detailed layout and padding treatment.
- Examples
- Uses bird records, calendar timestamps, nanosecond timestamps, nested person data, and a timespec difference exercise.
- What you can do after
- Apply C structure declarations, designated initializers, dot notation, heterogeneous fields, and nested member organization.
Learn Go with Pocket-Sized Projects
A struct is a Go composite data type that groups named fields of potentially different types into one value.
- How it is used
- Organizes related inputs, expected results, and decoded JSON records into reusable Go values.
- How deep it goes
- Demonstrates declarations, nested slices, JSON tags, and decoding, but does not descend into runtime internals.
- Examples
- Uses testCase scenarios and Bookworm–Book records as concrete struct examples.
- What you can do after
- Apply it via encoding/json to represent and decode structured records, or organize reusable table-driven test cases.
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Clojure: The Essential Reference
A Clojure struct is a map-like data structure with a defined set of keys and structural constraints.
- How it is used
- Creates many similarly shaped map-like values while avoiding repeated key declarations at each construction site.
- How deep it goes
- Defines the construction API and key constraints, then works through positional input, varying keys, accessors, equality, and exceptions.
- Examples
- Uses waypoint rows and coordinate maps to demonstrate positional construction, missing defined keys, extra keys, and accessor lookup.
- What you can do after
- Build it from scratch with create-struct or defstruct, then construct and query instances while respecting defined-key constraints.
Code Like a Pro in Rust
A compound type is a type formed by combining or grouping multiple values or component types.
- How it is used
- Uses structs to group state and attach operations behind an API.
- How deep it goes
- Explains struct forms, field visibility, methods, derived traits, and C-compatible representation; defers detailed generics.
- Examples
- Demonstrates tuple and named-field structs, visibility modifiers, receiver methods, and a zlib C struct mapping.
- What you can do after
- Build it from scratch: define stateful Rust APIs and map a C struct for a small FFI binding.
Rust in Action: Systems programming concepts and techniques
A struct is a Rust data structure that defines a composite value with named fields and their types.
- How it is used
- Models related values as one entity, especially files represented by names and byte data.
- How deep it goes
- Defines fields, instances, borrowing, memory composition, and constructors, while deferring persistent storage and detailed pointer explanations.
- Examples
- Uses File values containing String names and Vec<u8> data, simulated open/read/close operations, and File::new constructors.
- What you can do after
- Build it from scratch by defining structs, constructing instances, borrowing fields, and adding constructors or methods.
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Related concepts
- data structurekind of · A data structure is an organized representation of data and its relationships that supports defined operations for storing, accessing, or modifying it.
- Mapkind of · A map is an associative data structure that stores key-value pairs and supports retrieving values by key.
- concrete typekind of · A concrete type is a fully specified, directly implementable or instantiable type with a particular representation and behavior.
- defstruct macroused by · The defstruct macro defines the fields and initial values of a struct in an Elixir module.
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