How to combine two vectors of references without consuming an iterator?

Question

I want to combine two reference vectors and convert them into a vector of values without consuming an iterator.

Situation:

Generate vectors by iterating over specific combinations. (2 elements from one vector, 2 elements from another vector)

• Code:

use core::iter::Iterator;
use itertools::Itertools;

fn main() {
    let vec_a: Vec<u8> = vec![1, 2, 3];
    let vec_b: Vec<u8> = vec![4, 5, 6];

    // a: Vec<&u8>
    for a in vec_a.iter().combinations(2) {
        // b: Vec<&u8>
        for b in vec_b.iter().combinations(2) {
            // c: Vec<u8> <- a + b
            let c: Vec<u8> = a.clone().into_iter().chain(b).cloned().collect();
            println!("a: {:?}, b: {:?}, c: {:?}", a, b, c);
        }
    }
}

• Expected output:

a: [1, 2], b: [4, 5], c: [1, 2, 4, 5]
a: [1, 2], b: [4, 6], c: [1, 2, 4, 6]
a: [1, 2], b: [5, 6], c: [1, 2, 5, 6]
a: [1, 3], b: [4, 5], c: [1, 3, 4, 5]
a: [1, 3], b: [4, 6], c: [1, 3, 4, 6]
a: [1, 3], b: [5, 6], c: [1, 3, 5, 6]
a: [2, 3], b: [4, 5], c: [2, 3, 4, 5]
a: [2, 3], b: [4, 6], c: [2, 3, 4, 6]
a: [2, 3], b: [5, 6], c: [2, 3, 5, 6]

P.S.

I read the following link before posting my question. However, the answer to this question consumes Vec and its iterator, so it did not work in this situation.

Best way to concatenate vectors in Rust

Answer 1

Thanks to @ChayimFriedman.

There are some ways to do this.

• Without consumption

  // a: Vec<&u8>
  // b: Vec<&u8>
  
  let c: Vec<u8> = a.iter().chain(&b).copied().copied().collect();
  println!("a: {:?}", a);
  println!("b: {:?}", b);
  

• With consumption

  // a: Vec<&u8>
  // b: Vec<&u8>
  
  let c: Vec<u8> = a.into_iter().chain(b).copied().collect();
  // println!("a: {:?}", a); -> compile error
  // println!("b: {:?}", b); -> compile error