Rust Guide: How Closures Capture Environment Variables When Used with Iterators

Rust draws significant inspiration from functional programming, incorporating features such as closures and iterators that allow functions to be passed, returned, and stored as values. The filter method is an iterator adaptor that accepts a closure returning a boolean, including only elements for which the closure returns true. A practical example demonstrates this using a Shoe struct, where a shoes_in_size function filters a vector of shoes by matching each shoe's size field against a given value. The function uses into_iter to take ownership of the vector, applies filter with a capturing closure, and calls collect to return the matched results. This pattern illustrates how closures in Rust can capture variables from their surrounding scope to enable flexible, concise data processing.