Comparable
comparable is Go’s predeclared generic constraint satisfied by types whose values can be compared with == or !=.
Learn Go with Pocket-Sized Projects
comparable is Go's predeclared generic constraint satisfied by types whose values can be compared with == or !=.
- How it is used
- Constrains generic map and cache keys so equality-based lookup is valid.
- How deep it goes
- Defines equality support, enumerates comparable and non-comparable types, and applies the constraint in a generic cache.
- Examples
- Uses integer cache keys, string values, and a map[K]V declaration.
- What you can do after
- Build it from scratch by declaring generic map-backed types with equality-valid key parameters.
Read how Learn Go with Pocket-Sized Projects explains comparable →
Go in Action, Second Edition
comparable is a predeclared Go interface constraint satisfied by types whose values support equality and inequality comparisons.
- How it is used
- Constrains generic collection elements when operations such as removal and membership testing require equality.
- How deep it goes
- Works through a constrained type, constructor, and equality-based methods rather than comparison mechanics.
- Examples
- Uses a generic LinkedList constructor and Remove and Contains methods that compare stored values with an item.
- What you can do after
- Build it from scratch: declare a constrained linked list and implement equality-based collection operations.
100 Go Mistakes and How to Avoid Them
Comparable is a Go predeclared constraint satisfied by types whose values can be compared with == or !=.
- How it is used
- Restricts generic map keys to comparable types and helps distinguish valid equality tests from comparisons that fail.
- How deep it goes
- Explains the constraint through a generic function and traces compile-time errors versus a runtime comparison panic.
- Examples
- Uses generic key extraction, a struct changed to include a slice, and comparisons of values held in `any` variables.
- What you can do after
- Diagnose/debug with it when a map key or equality expression fails to compile, or an interface comparison panics.
Read how 100 Go Mistakes and How to Avoid Them explains comparable →
Related concepts
- type constraintkind of · A type constraint is a rule that restricts admissible types or type arguments by requiring specified relationships, structures, properties, or supported operations.
- linked listconfigures · An ordered sequence of elements stored in separate nodes connected by links or references rather than in one contiguous storage region.
- Comparable interfacekind of · Comparable is an interface, protocol, or mechanism that specifies whether values of a type can be compared or ordered.
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