Code shared from the Rust Playground

playground.rs

use std::collections::HashMap;

#[derive(Debug)]
pub struct NumberData {
    mean: f64,
    median: i32,
    mode: i32,
}
pub fn mean_median_mode(mut numbers: Vec<i32>) -> NumberData {
    numbers.sort();
    let mut sum: i32 = 0;
    let l = numbers.len();
    let mut middle = l / 2;
    if l % 2 == 0 {
        middle -= 1;
    };
    let mut occ = HashMap::new();
    let mut max_mode: i32 = 0;
    let mut mode_key: Option<i32> = None;
    for num in numbers.clone() {
        let count = occ.entry(num).or_insert(0);
        *count += 1;
        sum += num;
        if *count > max_mode {
            max_mode = *count;
            mode_key = Some(num);
        }
    }
    let median: i32 = numbers[middle];
    return NumberData {
        mean: sum as f64 / l as f64,
        median,
        mode: match mode_key {
            Some(x) => x,
            None => 0,
        },
    };
}

#[cfg(test)]
mod tests {
    #[test]
    fn it_works() {
        use super::*;
        let testvec = vec![0, 1, 2, 3, 4];
        let test_result = mean_median_mode(testvec);
        assert_eq!(test_result.mean, 2.0);
        assert_eq!(test_result.median, 2);
        assert_eq!(test_result.mode, 0);
    }
    #[test]
    fn it_also_works() {
        use super::*;
        let testvec = vec![187, -29, 3, 3, 3, -29, -39, -4];
        let test_result = mean_median_mode(testvec);
        assert_eq!(test_result.mean, 11.875);
        assert_eq!(test_result.median, -4);
        assert_eq!(test_result.mode, 3);
    }
}