How to Use Closures with Iterators in Rust

Combine closures with iterators in Rust by passing anonymous functions to methods like map or filter to process collections while capturing external variables.

Use closures with iterators by defining an anonymous function that captures variables and passing it to iterator methods like map, filter, or for_each.

let numbers = vec![1, 2, 3, 4, 5];
let multiplier = 2;

let doubled: Vec<i32> = numbers
    .iter()
    .map(|&n| n * multiplier)
    .collect();

println!("{:?}", doubled); // [2, 4, 6, 8, 10]

This pattern allows you to process collections declaratively while accessing external state.