// 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, value: Progress) -> usize { let mut count = 0; for val in map.values() { if val == &value { count += 1; } } count } fn count_iterator(map: &HashMap, 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], 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], 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 progressStates = vec![Progress::Complete, Progress::Some, Progress::None]; for progressState in progressStates { assert_eq!( count_for(&map, progressState), count_iterator(&map, progressState) ); } } #[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 progressStates = vec![Progress::Complete, Progress::Some, Progress::None]; let collection = get_vec_map(); for progressState in progressStates { assert_eq!( count_collection_for(&collection, progressState), count_collection_iterator(&collection, progressState) ); } } fn get_map() -> HashMap { 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> { 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] } }