Class timedelta

Lib/_pydatetime.py:624–952

Represent the difference between two datetime objects. Supported operators: - add, subtract timedelta - unary plus, minus, abs - compare to timedelta - multiply, divide by int In addition, datetime supports subtraction of two datetime objects returning a timedelta, and

class timedelta:
    """Represent the difference between two datetime objects.

    Supported operators:

    - add, subtract timedelta
    - unary plus, minus, abs
    - compare to timedelta
    - multiply, divide by int

    In addition, datetime supports subtraction of two datetime objects
    returning a timedelta, and addition or subtraction of a datetime
    and a timedelta giving a datetime.

    Representation: (days, seconds, microseconds).
    """
    # The representation of (days, seconds, microseconds) was chosen
    # arbitrarily; the exact rationale originally specified in the docstring
    # was "Because I felt like it."

    __slots__ = '_days', '_seconds', '_microseconds', '_hashcode'

    def __new__(cls, days=0, seconds=0, microseconds=0,
                milliseconds=0, minutes=0, hours=0, weeks=0):
        # Doing this efficiently and accurately in C is going to be difficult
        # and error-prone, due to ubiquitous overflow possibilities, and that
        # C double doesn't have enough bits of precision to represent
        # microseconds over 10K years faithfully.  The code here tries to make
        # explicit where go-fast assumptions can be relied on, in order to
        # guide the C implementation; it's way more convoluted than speed-
        # ignoring auto-overflow-to-long idiomatic Python could be.

        for name, value in (
            ("days", days),
            ("seconds", seconds),
            ("microseconds", microseconds),
            ("milliseconds", milliseconds),
            ("minutes", minutes),
            ("hours", hours),
            ("weeks", weeks)
        ):
            if not isinstance(value, (int, float)):
                raise TypeError(
                    f"unsupported type for timedelta {name} component: {type(value).__name__}"
                )

        # Final values, all integer.
        # s and us fit in 32-bit signed ints; d isn't bounded.
        d = s = us = 0

        # Normalize everything to days, seconds, microseconds.
        days += weeks*7
        seconds += minutes*60 + hours*3600
        microseconds += milliseconds*1000

        # Get rid of all fractions, and normalize s and us.
        # Take a deep breath <wink>.
        if isinstance(days, float):