duplicates()

Creates an array of unique elements from the first occurrence of each value in `array`.

Implementation

Args: array: List to process. iteratee: Function invoked per iteration. Returns: List of duplicates.

Example

duplicates([0, 1, 3, 2, 3, 1])

Expected output: [3, 1]

Source Code

                        def duplicates(array: List[T], iteratee: Callable[[T], Any] = lambda x: x) -> List[T]:
    seen: set = set()
    dup_set: set = set()
    result: List[T] = []
    for item in array:
        key = iteratee(item)
        if key in seen and key not in dup_set:
            dup_set.add(key)
            result.append(item)
        seen.add(key)
    return result
                    