leastOccurrences method

(T, int)? leastOccurrences()

Find the most common value in the list.

Implementation

(T, int)? leastOccurrences() {
  if (isEmpty) {
    return null;
  }

  // Create a new HashMap to store each integer and its frequency.
  final HashMap<T, int> frequencyMap = HashMap<T, int>();

  // Iterate over each integer in the list.
  for (final T item in this) {
    // Update the frequency of the current integer in the map,
    // or set it to 1 if it's not in the map yet.
    frequencyMap.update(item, (int value) => value + 1, ifAbsent: () => 1);
  }

  // Find and return the key with the highest value (frequency) in the map.
  final MapEntry<T, int>? leastCommonEntry = frequencyMap.entries.fold(
    null,
    (MapEntry<T, int>? previous, MapEntry<T, int> element) =>
        previous == null || element.value < previous.value ? element : previous,
  );

  if (leastCommonEntry == null) {
    return null;
  }

  // Return a tuple with the most common value and its frequency.
  return (leastCommonEntry.key, leastCommonEntry.value);
}