The book "Programming Rust" (very good book btw) only mentions iter() and iter_mut() briefly and focuses on into_iter because the IntoIterator trait only implem

The book "Programming Rust" (very good book btw) only mentions iter() and iter_mut() briefly and focuses on into_iter because the IntoIterator trait only implements into_iter. You can replicate iter() with `(&x).into_iter()` and you can replicate iter_mut() with `(&mut x).into_iter()` and obviously `x.into_iter()` consumes the contents.