rustlings/exercises/18_iterators/iterators5.rs

157 lines
4.4 KiB
Rust

// iterators5.rs
//
// Let's define a simple model to track Rustlings exercise progress. Progress
// will be modelled using a hash map. The name of the exercise is the key and
// the progress is the value. Two counting functions were created to count the
// number of exercises with a given progress. Recreate this counting
// functionality using iterators. Try not to use imperative loops (for, while).
// Only the two iterator methods (count_iterator and count_collection_iterator)
// need to be modified.
//
// Execute `rustlings hint iterators5` or use the `hint` watch subcommand for a
// hint.
// I AM NOT DONE
use std::collections::HashMap;
#[derive(Clone, Copy, PartialEq, Eq)]
enum Progress {
None,
Some,
Complete,
}
fn count_for(map: &HashMap<String, Progress>, value: Progress) -> usize {
let mut count = 0;
for val in map.values() {
if val == &value {
count += 1;
}
}
count
}
fn count_iterator(map: &HashMap<String, Progress>, value: Progress) -> usize {
// map is a hashmap with String keys and Progress values.
// map = { "variables1": Complete, "from_str": None, ... }
todo!();
}
fn count_collection_for(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
let mut count = 0;
for map in collection {
for val in map.values() {
if val == &value {
count += 1;
}
}
}
count
}
fn count_collection_iterator(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
// collection is a slice of hashmaps.
// collection = [{ "variables1": Complete, "from_str": None, ... },
// { "variables2": Complete, ... }, ... ]
todo!();
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn count_complete() {
let map = get_map();
assert_eq!(3, count_iterator(&map, Progress::Complete));
}
#[test]
fn count_some() {
let map = get_map();
assert_eq!(1, count_iterator(&map, Progress::Some));
}
#[test]
fn count_none() {
let map = get_map();
assert_eq!(2, count_iterator(&map, Progress::None));
}
#[test]
fn count_complete_equals_for() {
let map = get_map();
let progress_states = vec![Progress::Complete, Progress::Some, Progress::None];
for progress_state in progress_states {
assert_eq!(
count_for(&map, progress_state),
count_iterator(&map, progress_state)
);
}
}
#[test]
fn count_collection_complete() {
let collection = get_vec_map();
assert_eq!(
6,
count_collection_iterator(&collection, Progress::Complete)
);
}
#[test]
fn count_collection_some() {
let collection = get_vec_map();
assert_eq!(1, count_collection_iterator(&collection, Progress::Some));
}
#[test]
fn count_collection_none() {
let collection = get_vec_map();
assert_eq!(4, count_collection_iterator(&collection, Progress::None));
}
#[test]
fn count_collection_equals_for() {
let progress_states = vec![Progress::Complete, Progress::Some, Progress::None];
let collection = get_vec_map();
for progress_state in progress_states {
assert_eq!(
count_collection_for(&collection, progress_state),
count_collection_iterator(&collection, progress_state)
);
}
}
fn get_map() -> HashMap<String, Progress> {
use Progress::*;
let mut map = HashMap::new();
map.insert(String::from("variables1"), Complete);
map.insert(String::from("functions1"), Complete);
map.insert(String::from("hashmap1"), Complete);
map.insert(String::from("arc1"), Some);
map.insert(String::from("as_ref_mut"), None);
map.insert(String::from("from_str"), None);
map
}
fn get_vec_map() -> Vec<HashMap<String, Progress>> {
use Progress::*;
let map = get_map();
let mut other = HashMap::new();
other.insert(String::from("variables2"), Complete);
other.insert(String::from("functions2"), Complete);
other.insert(String::from("if1"), Complete);
other.insert(String::from("from_into"), None);
other.insert(String::from("try_from_into"), None);
vec![map, other]
}
}