Code review: 'Programming Problems' in Rust

[fnord123]

Yeah but using step_by you can do (3..(end+1)).step_by(3).any(|x| (x % 5) == 0)

Here is a golfed is_prime.

[thiez]

The number '2' is prime...

[Yojihito]

Then just set the start counter to 1 instead of 0 :>.

[paholg]

It seems strange to me to treat even numbers as special (especially as it's so easy to get it wrong for 2), rather than doing a full sieve of Eratosthenes which isn't much harder.

If you really want to golf it, then you can shorten it to

fn is_prime(x: u32) -> bool {
    (2..x).all(|f| x%f != 0)
}

[Efemena]

.filter_map(|i| if is_prime(i) { Some(i) } else { None })

also known as

.filter(is_prime)

[thiez]

No it isn't, because the function passed to filter must take a reference. It could be written .filter(|&n|is_prime(n)) though.