Using Closures with Iterators

Snippet

Using Closures with Iterators

Closures are anonymous functions that capture their environment. Combined with iterators, they enable powerful functional programming patterns. The filter method uses a closure to decide which elements to keep, while map transforms each element.

snippet.rs
rust
fn main() {
    let numbers = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
    
    let doubled: Vec<i32> = numbers
        .iter()
        .filter(|&&x| x % 2 == 0)
        .map(|x| x * 2)
        .collect();
    
    println!("Even numbers doubled: {:?}", doubled);
}

Breakdown

.iter()

Creates an iterator that borrows vector elements

.filter(|&&x| x % 2 == 0)

Closure keeps only even numbers, &&x needed to dereference the reference

.map(|x| x * 2)

Closure multiplies each value by 2

.collect()

Transforms iterator back into a collection

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Using Closures with Iterators

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