zip_clone

Zip an iterator to a repeatedly cloned object.

Pass an owned object that implements Clone to create an iterator that zips the original iterator with clones of the object.

One iteration returns the original object, hence using one fewer clones than iter.zip(repeat_with(|| cloned.clone())).

This is useful for loops where a value is cloned for each iteration, but is not used after the iteration.

Instead of cloning a value 10 times using:

let mut v = vec![String::new(); 10];
let s = String::from("Hello");
for i in 0..10 {
    v[i] = s.clone();
}

clone the value 9 times using:

use zip_clone::ZipClone as _;

let mut v = vec![String::new(); 10];
let s = String::from("Hello");
for (i, s) in (0..10).zip_clone(s) {
    v[i] = s;
}

This is especially useful when an iterator usually returns a single value, to avoid expensive cloning for the common case:

use zip_clone::ZipClone as _;

let home_city = "Birmingham"; // use ; if person claims multiple home cities
let mut v = vec![];
let s = String::from("Hello from ");
for (city, mut message) in home_city.split(';').zip_clone(s) {
    message.push_str(city);
    v.push(message);
}

zip_clone avoids cloning if items are skipped. The following code uses the original String for the single value produced, avoiding any cloning.

use zip_clone::ZipClone as _;

let s = String::from("Hello");
let _ = (0..10).zip_clone(s).last();