Class Span

src/licensedcode/spans.py:42–474

Represent ranges of integers (such as tokens positions) as a set of integers. A Span is hashable and not meant to be modified once created, like a frozenset. It is equivalent to a sparse closed interval. Originally derived and heavily modified from Whoosh Span.

class Span(Set):
    """
    Represent ranges of integers (such as tokens positions) as a set of integers.
    A Span is hashable and not meant to be modified once created, like a frozenset.
    It is equivalent to a sparse closed interval.
    Originally derived and heavily modified from Whoosh Span.
    """

    def __init__(self, *args):
        """
        Create a new Span from a start and end ints or an iterable of ints.

        First form:
        Span(start int, end int) : the span is initialized with a range(start, end+1)

        Second form:
        Span(iterable of ints) : the span is initialized with the iterable

        Spans are hashable and immutable.

        For example:
        >>> s = Span(1)
        >>> s.start
        1
        >>> s = Span([1, 2])
        >>> s.start
        1
        >>> s.end
        2
        >>> s
        Span(1, 2)

        >>> s = Span(1, 3)
        >>> s.start
        1
        >>> s.end
        3
        >>> s
        Span(1, 3)

        >>> s = Span([6, 5, 1, 2])
        >>> s.start
        1
        >>> s.end
        6
        >>> s
        Span(1, 2)|Span(5, 6)
        >>> len(s)
        4

        >>> Span([5, 6, 7, 8, 9, 10 ,11, 12]) == Span([5, 6, 7, 8, 9, 10 ,11, 12])
        True
        >>> hash(Span([5, 6, 7, 8, 9, 10 ,11, 12])) == hash(Span([5, 6, 7, 8, 9, 10 ,11, 12]))
        True
        >>> hash(Span([5, 6, 7, 8, 9, 10 ,11, 12])) == hash(Span(5, 12))
        True
        """
        len_args = len(args)