Files
chapter-8-exercises/src/stats.rs
2020-11-24 11:26:26 +00:00

145 lines
3.5 KiB
Rust

use ::std::collections::HashMap;
use std::convert::TryFrom;
#[derive(Debug)]
pub struct NewStatsCalculator {
data: Vec<i32>,
length: u32,
total: i32,
}
impl NewStatsCalculator {
pub fn from_vec(initial_data: &[i32]) -> Self {
let initial_data = initial_data.to_vec();
let mut instance = NewStatsCalculator {
data: initial_data,
length: 0,
total: 0,
};
instance.get_length();
instance.get_total();
instance
}
// pub fn initialise(&mut self) -> () {
// self.total = self.data.iter().sum();
// let length = i32::try_from(self.data.len());
// // self.length = match length {
// // Ok(i) => i,
// // _ => 0,
// // };
// if let Ok(i) = length {
// self.length = i;
// } else {
// self.length = 0;
// }
// }
fn get_length(&mut self) {
let length = u32::try_from(self.data.len());
if let Ok(i) = length {
self.length = i;
} else {
self.length = 0;
}
}
fn get_total(&mut self) {
self.total = self.data.iter().sum();
}
pub fn get_mean(&self) -> f32 {
self.total as f32 / self.length as f32
}
pub fn get_median(&mut self) -> f32 {
let mid = self.length as usize / 2;
self.data.sort_unstable();
if self.length % 2 == 0 {
(self.data[mid - 1] as f32 + self.data[mid] as f32) / 2.0
} else {
self.data[mid] as f32
}
}
pub fn get_mode(&self) -> Option<(i32, i32)> {
let mut mode: HashMap<i32, i32> = HashMap::new();
for i in &self.data {
let count = mode.entry(*i).or_insert(0);
*count += 1;
}
let mut mode_value: Option<(i32, i32)> = mode
.iter()
.max_by(|a, b| a.1.cmp(b.1))
.map(|(k, v)| (*k, *v));
if let Some((_, v)) = mode_value {
if v == 1 {
mode_value = None
}
}
// println!("{:?}", mode_value);
mode_value
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_get_length() {
let data = vec![1, 2, 3, 4, 5, 6];
let mut test = NewStatsCalculator::from_vec(&data);
test.get_length();
assert_eq!(test.length, 6);
}
#[test]
fn test_get_total() {
let data = vec![1, 2, 3, 4, 5, 6];
let mut test = NewStatsCalculator::from_vec(&data);
test.get_length();
assert_eq!(test.total, 21);
}
#[test]
fn test_get_mean() {
let data = vec![1, 2, 3, 4, 5, 6];
let test = NewStatsCalculator::from_vec(&data);
assert_eq!(test.get_mean(), 3.5);
}
#[test]
fn test_get_median_even() {
let data = vec![1, 2, 3, 4, 5, 6];
let mut test = NewStatsCalculator::from_vec(&data);
assert_eq!(test.get_median(), 3.5);
}
#[test]
fn test_get_median_odd() {
let data = vec![1, 2, 3, 4, 5, 6, 7];
let mut test = NewStatsCalculator::from_vec(&data);
assert_eq!(test.get_median(), 4.0);
}
#[test]
fn test_get_mode_with_mode() {
let data = vec![1, 2, 3, 4, 5, 6, 6];
let test = NewStatsCalculator::from_vec(&data);
assert_eq!(test.get_mode(), Some((6, 2)))
}
#[test]
fn test_get_mode_without_mode() {
let data = vec![1, 2, 3, 4, 5, 6];
let test = NewStatsCalculator::from_vec(&data);
assert_eq!(test.get_mode(), None)
}
}