Rust from

Rust from_iter

Created By: chatGPT

Rust provides a powerful way to work with collections and iterators through the iter method. The iter method is used to create an iterator over the elements of a collection, allowing you to perform transformations and computations in a functional style. Below, we will explore how to use iter in different scenarios.

let vec = vec![1, 2, 3, 4, 5];
let iter = vec.iter();

In this example, we create a vector of integers and then obtain an iterator using the iter method. The iterator can be used to traverse through the elements of the vector without consuming it. This is particularly useful when you want to maintain access to the original collection.

for val in iter {
    println!("Value: {}", val);
}

You can also use iter in combination with methods such as map, filter, and collect to perform functional programming operations. For instance, if you want to create a new vector containing the squares of the original values, you can do it as follows:

let squares: Vec<i32> = vec.iter() // Get the iterator
    .map(|&x| x * x) // Square each value
    .collect(); // Collect into a new vector

Additionally, you can use the filter method to extract only the even numbers from the vector. Here's how you can implement that:

let evens: Vec<i32> = vec.iter() // Get the iterator
    .filter(|&&x| x % 2 == 0) // Keep only even numbers
    .cloned() // Convert references to values
    .collect(); // Collect into a new vector

Combining various iterator methods can lead to concise and expressive code. For example, suppose you want to obtain the sum of the squares of all even numbers in the vector. You can achieve this with a single line:

let sum_of_squares_of_evens: i32 = vec.iter()
    .filter(|&&x| x % 2 == 0)
    .map(|&x| x * x)
    .sum();