What are structs in Julia?

Updated May 16, 2026

Short answer

Structs define custom composite data types in Julia.

Deep explanation

Structs group related data fields. By default, they are immutable, improving performance and enabling compiler optimizations. Mutable structs allow modification but are slower.

Real-world example

Used to represent entities like particles in simulations.

Common mistakes

  • Using mutable structs unnecessarily, hurting performance.

Follow-up questions

  • When should you use mutable struct?

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