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Issue #23517: datetime.timedelta constructor now rounds microseconds to nearest

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with ties going away from zero (ROUND_HALF_UP), as Python 2 and Python older
than 3.3, instead of rounding to nearest with ties going to nearest even
integer (ROUND_HALF_EVEN).
This commit is contained in:
Victor Stinner 2015-09-02 19:16:07 +02:00
parent 8cbb013553
commit 2ec558739e
6 changed files with 26 additions and 34 deletions
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12
Lib/datetime.py
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@ -316,6 +316,14 @@ def _divide_and_round(a, b):
return q
def _round_half_up(x):
"""Round to nearest with ties going away from zero."""
if x >= 0.0:
return _math.floor(x + 0.5)
else:
return _math.ceil(x - 0.5)
class timedelta:
"""Represent the difference between two datetime objects.
@ -399,7 +407,7 @@ class timedelta:
# secondsfrac isn't referenced again
if isinstance(microseconds, float):
microseconds = round(microseconds + usdouble)
microseconds = _round_half_up(microseconds + usdouble)
seconds, microseconds = divmod(microseconds, 1000000)
days, seconds = divmod(seconds, 24*3600)
d += days
@ -410,7 +418,7 @@ class timedelta:
days, seconds = divmod(seconds, 24*3600)
d += days
s += seconds
microseconds = round(microseconds + usdouble)
microseconds = _round_half_up(microseconds + usdouble)
assert isinstance(s, int)
assert isinstance(microseconds, int)
assert abs(s) <= 3 * 24 * 3600