Rust mean, median, mode algorithms
// Rust mean, median, mode algorithms with examples of use
fn mean(arr: &[f64]) -> f64 {
let sum = arr.iter().fold(0.0, |p,&q| p + q);
sum / arr.len() as f64
}
fn median(mut xs: Vec<f64>) -> f64 {
// sort in ascending order, panic on f64::NaN
xs.sort_by(|x,y| x.partial_cmp(y).unwrap() );
let n = xs.len();
if n % 2 == 0 {
(xs[n/2] + xs[n/2 - 1]) / 2.0
} else {
xs[n/2]
}
}
fn mode(vs: Vec<i32>) -> Vec<i32> {
use std::collections::HashMap;
let mut vec_mode = Vec::new();
let mut seen_map = HashMap::new();
let mut max_val = 0;
for i in vs{
let ctr = seen_map.entry(i).or_insert(0);
*ctr += 1;
if *ctr > max_val{
max_val = *ctr;
}
}
for (key, val) in seen_map {
if val == max_val{
vec_mode.push(key);
}
}
vec_mode
}
fn main() {
let v = &[2.0, 3.0, 5.0, 7.0, 13.0, 21.0, 33.0, 54.0];
println!("mean of {:?}: {:?}", v, mean(v));
let w = &[];
println!("mean of {:?}: {:?}", w, mean(w));
println!("median of {:?}: {:?}", v, median(v.to_vec()));
let mode_vec1 = mode(vec![ 1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]);
let mode_vec2 = mode(vec![ 1, 1, 2, 4, 4]);
println!("Mode of vec1 is: {:?}", mode_vec1);
println!("Mode of vec2 is: {:?}", mode_vec2);
}