diff options
| -rw-r--r-- | exercises/standard_library_types/iterators5.rs | 51 | ||||
| -rw-r--r-- | info.toml | 11 |
2 files changed, 37 insertions, 25 deletions
diff --git a/exercises/standard_library_types/iterators5.rs b/exercises/standard_library_types/iterators5.rs index 65c50e6..2d97bd4 100644 --- a/exercises/standard_library_types/iterators5.rs +++ b/exercises/standard_library_types/iterators5.rs @@ -1,11 +1,14 @@ // iterators5.rs -// Rustling progress is 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. These counting -// functions use imperative style for loops. Recreate this counting -// functionality using iterators. -// Execute `rustlings hint iterators5` for hints. +// 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. These counting functions use +// imperative style for loops. Recreate this counting functionality using +// iterators. Only the two iterator methods (count_iterator and +// count_collection_iterator) need to be modified. +// Execute `rustlings hint +// iterators5` for hints. // // Make the code compile and the tests pass. @@ -30,12 +33,14 @@ fn count_for(map: &HashMap<String, Progress>, value: Progress) -> usize { count } -fn count(map: &HashMap<String, Progress>, value: Progress) -> usize { +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, ... } } -fn count_stack_for(stack: &[HashMap<String, Progress>], value: Progress) -> usize { +fn count_collection_for(collection: &[HashMap<String, Progress>], value: Progress) -> usize { let mut count = 0; - for map in stack { + for map in collection { for val in map.values() { if val == &value { count += 1; @@ -45,7 +50,10 @@ fn count_stack_for(stack: &[HashMap<String, Progress>], value: Progress) -> usiz count } -fn count_stack(stack: &[HashMap<String, Progress>], value: Progress) -> usize { +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, ... }, ... ] } #[cfg(test)] @@ -55,7 +63,7 @@ mod tests { #[test] fn count_complete() { let map = get_map(); - assert_eq!(3, count(&map, Progress::Complete)); + assert_eq!(3, count_iterator(&map, Progress::Complete)); } #[test] @@ -63,22 +71,25 @@ mod tests { let map = get_map(); assert_eq!( count_for(&map, Progress::Complete), - count(&map, Progress::Complete) + count_iterator(&map, Progress::Complete) ); } #[test] - fn count_stack_complete() { - let stack = get_map_stack(); - assert_eq!(6, count_stack(&stack, Progress::Complete)); + fn count_collection_complete() { + let collection = get_vec_map(); + assert_eq!( + 6, + count_collection_iterator(&collection, Progress::Complete) + ); } #[test] - fn count_stack_equals_for() { - let stack = get_map_stack(); + fn count_collection_equals_for() { + let collection = get_vec_map(); assert_eq!( - count_stack_for(&stack, Progress::Complete), - count_stack(&stack, Progress::Complete) + count_collection_for(&collection, Progress::Complete), + count_collection_iterator(&collection, Progress::Complete) ); } @@ -96,7 +107,7 @@ mod tests { map } - fn get_map_stack() -> Vec<HashMap<String, Progress>> { + fn get_vec_map() -> Vec<HashMap<String, Progress>> { use Progress::*; let map = get_map(); @@ -694,7 +694,7 @@ Step 2 & step 2.1: Very similar to the lines above and below. You've got this! Step 3: An iterator goes through all elements in a collection, but what if we've run out of -elements? What should we expect here? If you're stuck, take a look at +elements? What should we expect here? If you're stuck, take a look at https://doc.rust-lang.org/std/iter/trait.Iterator.html for some ideas. """ @@ -749,12 +749,13 @@ hint = """ The documentation for the std::iter::Iterator trait contains numerous methods that would be helpful here. -Return 0 from count_stack to make the code compile in order to test count. +Return 0 from count_collection_iterator to make the code compile in order to +test count_iterator. -The stack variable in count_stack is a slice of HashMaps. It needs to be -converted into an iterator in order to use the iterator methods. +The collection variable in count_collection_iterator is a slice of HashMaps. It +needs to be converted into an iterator in order to use the iterator methods. -The fold method can be useful in the count_stack function.""" +The fold method can be useful in the count_collection_iterator function.""" # THREADS |