Day 13h: Vector Transformation and Functional Programming Techniques

Day 13h: Vector Transformation and Functional Programming Techniques

Introduction

Rust supports powerful functional programming techniques when working with vectors. In this session, we’ll explore transformations using map(), filter(), and more. We'll also look at chaining multiple iterator methods to achieve complex operations.

Transforming Vectors with map()

The map() method applies a function to each element in the vector, transforming it into a new vector. Here’s how it works:

fn main() {

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

    let squares: Vec<i32> = numbers.iter().map(|&x| x * x).collect();

    println!("{:?}", squares);  // Output: [1, 4, 9, 16]

}

Filtering Elements with filter()

The filter() method allows you to retain only the elements that satisfy a condition.

fn main() {

    let numbers = vec![1, 2, 3, 4, 5, 6];

    let evens: Vec<i32> = numbers.into_iter().filter(|&x| x % 2 == 0).collect();

    println!("{:?}", evens);  // Output: [2, 4, 6]

}

Chaining Iterators

You can chain multiple iterator methods together for more complex transformations. This is both efficient and expressive.

fn main() {

    let numbers = vec![1, 2, 3, 4, 5, 6];

    let result: Vec<i32> = numbers

        .into_iter()

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

        .map(|x| x * x)

        .collect();

    println!("{:?}", result);  // Output: [4, 16, 36]

}

Conclusion

Functional programming techniques like map() and filter() provide a clean and efficient way to transform vectors in Rust. Chaining iterators allows you to perform complex transformations in a concise manner.