Function itertools::merge

pub fn merge<I, J>(
    i: I,
    j: J,
) -> Merge<<I as IntoIterator>::IntoIter, <J as IntoIterator>::IntoIter> 
where
    I: IntoIterator,
    J: IntoIterator<Item = I::Item>,
    I::Item: PartialOrd,

Create an iterator that merges elements in i and j.

IntoIterator enabled version of i.merge(j).

use itertools::merge;

for elt in merge(&[1, 2, 3], &[2, 3, 4]) {
    /* loop body */
}