Javascript或Python如何判断是白天还是夜晚？

Question

知道我如何根据用户的时间和位置判断当前是晚上/白天还是日出/黎明？

我没有发现任何有用的东西可以在客户端或后端使用。在

让它变得棘手的是，小时并不一定定义它是否是黑夜和白天，这在很大程度上取决于年、月、日、时和地理坐标。在

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为了澄清。。。模仿这样的东西。在

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一种近似的方法也非常有用。

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希望有人能帮忙！在

Answer 1

你可以像我一样，使用这个公共域Sun.py模块来计算太阳相对于地球位置的位置。它很旧，但多年来对我很管用。我对它做了一些表面上的修改，使之更能适应Python2.7的最新版本，比如使其中的几个类成为新样式，但在大多数情况下它没有改变。在

这是我创建的一个模块，名为日出集.py，它展示了如何使用它来计算给定地理坐标和时区的特定位置的日出和日落时间。引用的timezone模块是datetime模块文档中描述的^{}抽象基类的实现。在

# -*- coding: iso-8859-1 -*-
import datetime
import timezone  # concrete tzinfo subclass based on the Python docs
import math
from Sun import Sun

__all__ = ['getsuninfo', 'Place']

class Place(object):
    def __init__(self, name, coords, tz=timezone.Pacific):
        self.name = name        # string
        self.coords = coords    # tuple (E/W long, N/S lat)
        self.tz = tz            # tzinfo constant

def _hoursmins(hours):
    """Convert floating point decimal time in hours to integer hrs,mins"""
    frac,h = math.modf(hours)
    m = round(frac*60, 0)
    if m == 60: # rounded up to next hour
        h += 1; m = 0
    return int(h),int(m)

def _ymd(date):
    """Return y,m,d from datetime object as tuple"""
    return date.timetuple()[:3]

def getsuninfo(location, date=None):
    """Return local datetime of sunrise, sunset, and length of day in hrs,mins)"""
    if date == None:
        querydate = datetime.date.today()
    else: # date given should be datetime instance
        querydate = date

    args = _ymd(querydate) + location.coords
    utcrise, utcset = Sun().sunRiseSet(*args)
    daylength = Sun().dayLength(*args)
    hrs,mins = _hoursmins(daylength)

    risehour, risemin = _hoursmins(utcrise)
    sethour, setmin   = _hoursmins(utcset)

    # convert times to timedelta values (ie from midnight utc of the date)
    midnight = datetime.datetime(tzinfo=timezone.utc, *_ymd(querydate))
    deltarise = datetime.timedelta(hours=risehour, minutes=risemin)
    utcdatetimerise = midnight+deltarise
    deltaset = datetime.timedelta(hours=sethour, minutes=setmin)
    utcdatetimeset  = midnight+deltaset

    # convert results from UTC time to local time of location
    localrise = utcdatetimerise.astimezone(location.tz)
    localset  = utcdatetimeset.astimezone(location.tz)

    return localrise, localset, hrs, mins

if __name__ == "__main__":
    import datetime, timezone

    def unittest(location, testdate):
        risetime, settime, hrs, mins = getsuninfo(location, testdate)

        print "Location:", location.name
        print "Date:", testdate.strftime("%a %x")
        print risetime.strftime("Sunrise %I:%M %p"), settime.strftime("- Sunset %I:%M %p (%Z)")
        print "daylight: %d:%02d" % (hrs,mins)
        print

    place = Place("My House", (-121.990278, 47.204444), timezone.Pacific)

    # test dates just before and after DST transitions
    print "pre 2007"
    print "========="
    unittest(place, datetime.date(2006, 4, 1))
    unittest(place, datetime.date(2006, 4, 2))
    unittest(place, datetime.date(2006, 10, 28))
    unittest(place, datetime.date(2006, 10, 29))

    print "2007"
    print "========="
    unittest(place, datetime.date(2007, 3, 10))
    unittest(place, datetime.date(2007, 3, 11))
    unittest(place, datetime.date(2007, 11, 3))
    unittest(place, datetime.date(2007, 11, 4))