Joel Medicala

Deep Flattening in Rust: A Recursive Adventure​

Flattening nested data structures is a common problem in programming. However, flattening structures with an arbitrary depth—like nested Vecs within Vecs—can be tricky. Rust, with its strong type system and trait-based polymorphism, allows us to implement elegant solutions to such problems. In this post, we'll explore a recursive approach to deep flattening in Rust using traits, type inference, and iterators.

The Goal​

Given a deeply nested structure, such as:

let nested_vec = vec![
    vec![vec![1, 2, 3], vec![4, 5]],
    vec![vec![6], vec![7, 8, 9]],
];

Our goal is to flatten it into:

let flattened = vec![1, 2, 3, 4, 5, 6, 7, 8, 9];