Standard deviation in Rust

std_deviation.rs

fn mean(data: &[u32]) -> f64 {
    let sum = data.iter().sum::<u32>() as f64;
    let count = data.len();
    sum / count as f64
}

fn std_deviation(data: &[u32]) -> f64 {
    if data.len() != 0 {
        let data_mean = mean(data);
        let variance = data.iter().map(|v| {
            let diff = (*v as f64) - data_mean;
            diff * diff
        }).sum::<f64>() / data.len() as f64;
        variance.sqrt()
    } else {
        0.0
    }
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    //let data = [3, 1, 6, 1, 5, 8, 1, 8, 10, 11];
    let data = [1, 1, 1, 1, 1, 2];
    let data_std_deviation = std_deviation(&data);
    println!("Standard deviation is {}", data_std_deviation);

    Ok(())
}

$ ./rust-test
Standard deviation is 0.3726779962499649