What is a stable way to iterate on a range with custom step?

Question

How should I go if I want to iterate with a custom step in stable Rust? Essentially something like the C/C++

for (in         


        

Answer 1

You can use the iterator_step_by feature.

Here is an example of two threads running, one of them printing out odd numbers and the other even ones:

#![feature(iterator_step_by)]
extern crate thebook;

use std::thread;
use std::time::Duration;
fn main() {
    let handle = thread::spawn(|| {
        for i in (1..1000).step_by(2) {
            println!("{}", i);
        }
    });
    for i in (2..1000).step_by(2) {
        println!("{}", i);
    }
    handle.join();
}

Without this feature, you can also use a filter on the range:

use std::thread;
use std::time::Duration;
fn main() {
    let handle = thread::spawn(|| {
        for i in (1..1000).filter(|x| x % 2 != 0) {
            println!("{}", i);
        }
    });
    for i in (2..1000).filter(|x| x % 2 == 0) {
        println!("{}", i);
    }
    handle.join();
}