下面的代码应该:
将输入字符串解析为某种持续时间
验证持续时间不为空,不为负,不超过10年
输入字符串的示例是:
duration_string = "P10W"
duration_string = "P1Y"
这是代码
duration = isodate.parse_duration(duration_string)
if isinstance(duration, datetime.timedelta):
if not duration > datetime.timedelta(0):
raise Exception('duration invalid')
if duration > datetime.timedelta(3660):
raise Exception('duration cannot be longer than 10 years')
elif isinstance(duration, isodate.Duration):
if not duration > 0:
raise Exception('duration invalid')
if duration > isodate.duration.Duration(0, 0, 0, years=10, months=0):
log.debug("duration %s isodate %s" % (duration, isodate.duration.Duration(0, 0, 0, years=10, months=0)))
raise Exception('duration cannot be longer than 10 years')
有比我产生的怪诞更简单的方法吗?
除了需要简化之外,行
duration > isodate.duration.Duration(0, 0, 0, years=10, months=0)
不起作用。我正在使用Python 2.7
最佳答案
好的,因此,如果您绝对必须使用isodate持续时间解析,请保留isodate
库。但是,我要提到isodate库不完整,有许多糟糕的设计决策,而且通常是不好的。
但是,如果必须使用他们的解析工具,这可能是一个好方法。
import isodate
import functools
@functools.total_ordering # if we implement < ==, will implement <=, >, >=
class Duration(isodate.Duration):
# inherit from isodate.Duration -- gives us ==
# constants
seconds_in_day = 60**2 * 24
approx_days_in_month = 30
approx_days_in_year = 365
def approx_total_seconds(self):
"""approx total seconds in duration"""
# self.months and self.years are stored as `Decimal`s for some reason...
return self.tdelta.total_seconds() \
+ float(self.months) * self.approx_days_in_month * self.seconds_in_day \
+ float(self.years) * self.approx_days_in_year * self.seconds_in_day
def __lt__(self, other):
"""defines self < other"""
if not isinstance(other, Duration):
return NotImplemented
return self.approx_total_seconds() < other.approx_total_seconds()
@classmethod
def parse_duration(cls, datestring):
"""a version of isodate.parse_duration that returns out class"""
iso_dur = isodate.parse_duration(datestring)
# iso_date.parse_duration can return either a Duration or a timedelta...
if isinstance(iso_dur, isodate.Duration):
return cls(seconds=iso_dur.tdelta.total_seconds(),
months=iso_dur.months, years=iso_dur.years)
else:
return cls(seconds=iso_dur.total_seconds())
ten_weeks = Duration.parse_duration('P10W')
one_year = Duration.parse_duration('P1Y')
print(ten_weeks.approx_total_seconds())
print(one_year.approx_total_seconds())
print(ten_weeks < one_year)
print(ten_weeks > one_year)
产出
6048000.0
31536000.0
True
False
如果您不需要isodate解析(我怀疑您不需要),则可以这样做
@functools.TotalOrdering
class ApproxTimeDelta:
approx_days_in_week = 7
approx_days_in_month = 30
approx_days_in_year = 365
def __init__(self, days, weeks, months, years):
self.days = days + \
weeks * self.approx_days_in_week + \
months * self.approx_days_in_month + \
years * self.approx_days_in_year
def __eq__(self, other):
return self.days == other.days
def __lt__(self, other):
return self.days < other.days
并以整数形式传递年/月/周/日,并像以前一样进行比较。