Python 基于日期和时间创建对象

我有一个活动模型，每个活动都有不同的表演

class Event(models.Model):
    title = models.CharField(max_length=200)

class Show(models.Model):
    event = models.ForeignKey(Event, on_delete=models.CASCADE)
    date_time = models.DateTimeField(unique=True)

我有另一种票型。每张票都应该是唯一的。这意味着每张票都是独一无二的，并且与一场演出和一个座位有关

class Ticket(models.Model):
    show = models.ForeignKey(Show)
    seat = models.ForeignKey(Seat)

    class Meta:
        unique_together = ('show', 'seat')

我需要根据用户提供的开始日期和结束日期创建节目。假设这是一篇JSON文章：

{
    "event_id": 1,
    "start_date": "2018-02-16",
    "end_date": "2018-02-20",
    "time_list": ["11:00 AM", "8:00 PM"]
}

根据上面的JSON示例，我需要创建如下开头的Show：

# Start with the start_date as the date, and for each time from the time_list
Show.objects.create(
    event = 1,
    date_time = datetime.strptime('2018-02-16 11:00 AM', "%Y-%m-%d %I:%M %p")
)
Show.objects.create(
    event = 1,
    date_time = datetime.strptime('2018-02-16 8:00 PM', "%Y-%m-%d %I:%M %p")
)
# Next date after the start_date, i.e., 16+1 = 17
Show.objects.create(
    event = 1,
    date_time = datetime.strptime('2018-02-17 8:00 PM', "%Y-%m-%d %I:%M %p")
)
.
.
.
# Create Show objects till the end_date and for each time from the time_list
Show.objects.create(
    event = 1,
    date_time = datetime.strptime('2018-02-20 8:00 PM', "%Y-%m-%d %I:%M %p")
)

现在，这就是我创建Show对象的方式：

def create_show_by_datetime(self, request):
    event_id = request.data['event_id']
    try:
        event = Event.objects.get(id=event_id)
    except Event.DoesNotExist:
        return Response(
            {'error': 'event with id: %s does not exist.' % event_id},
            status=status.HTTP_400_BAD_REQUEST
        )

    start_date = request.data['start_date']
    end_date = request.data['end_date']
    time_list = request.data['time_list']
    date_format = '%Y-%m-%d'
    time_format = "%I:%M %p"
    try:
        datetime.strptime(start_date, date_format)
        datetime.strptime(end_date, date_format)
        for i in range(len(time_list)):
            time = datetime.strptime(time_list[i], time_format)
    except ValueError as e:
        return Response(
            {'error': 'Time was not in a supported format. %s' % e},
            status=status.HTTP_400_BAD_REQUEST
        )

    delta_days = datetime.strptime(end_date, date_format).date() - datetime.strptime(start_date, date_format).date()
    delta_days = delta_days.days + 1
    dt = None
    try:
        with transaction.atomic():
            for i in range(delta_days):
                day = datetime.strptime(start_date, date_format) + timedelta(days=i)
                for i in range(len(time_list)):
                    hrs = datetime.strptime(time_list[i], time_format).hour
                    mins = datetime.strptime(time_list[i], time_format).minute
                    dt = day + timedelta(hours=hrs, minutes=mins)
                    show = Show.objects.create(
                        event=event,
                        date_time=dt
                    )
            return Response({"data": 'Post succesfull'}, status=status.HTTP_201_CREATED)
    except IntegrityError as e:
        return Response(
            {
                'error': "event with date and time already exsits. %s-%s-%s at %s:%s" % (
                    dt.day, dt.month, dt.year, dt.hour, dt.minute),
                'detail': str(e)
            }, status=status.HTTP_400_BAD_REQUEST

---

但我希望有比我现在做的更优雅的方式。我正在使用python 3、django 2和django rest框架工作。如何根据

事件id

、

开始日期

、

结束日期

和

时间列表

创建带有事件的显示和日期时间？

那么您的

显示

模型应该是这样的

from django.contrib.postgres.fields import ArrayField

class Show(models.Model):
    event = models.ForeignKey(Event, on_delete=models.CASCADE)
    start_date = models.DateField(blank=True, null=True)
    end_date = models.DateField(blank=True, null=True)
    board = ArrayField(
        models.TimeField(blank=True, null=True),
        size=10, # specify max array size
    )

因此，您将使用指定的

日期字段和
时间字段数组创建模型
Show

django docs:，
我将离开验证部分，只关注从给定数据生成
Show
对象：

data = request.data

date_format = '%Y-%m-%d'
time_format = "%I:%M %p"
show_time_format = f"{date_format} {time_format}"

# get the total number of days by parsing start and end dates
start_date = datetime.strptime(data['start_date'], date_format)
end_date = datetime.strptime(data['end_date'], date_format)
total_days = (end_date - start_date).days + 1

# Get the timings for the first day.
# We will use this to generate the timings for the rest of the days.
first_day_timings = [
    datetime.strptime(f"{data['start_date']} {show_time}", show_time_format)
    for show_time in data['time_list']
]

# generate all show objects using list comprehension and bulk create later
show_objects = [
    Show(event=event, date_time=first_day_timing + timedelta(days=day_cnt))
    for day_cnt in range(total_days)
    for first_day_timing in first_day_timings
]

Show.objects.bulk_create(show_objects)

对现有代码所做的增强：

减少了实例数—解析日期/时间和计算小时/分钟
使用列表理解生成显示对象和批量创建，而不是在事务中一次创建一个对象
datetime库中有一些工具可以为您提供一种更简化的生成时间的方法。您可以使用
toordinal
将日期转换为整数，使用
fromordinal
将整数转换回日期；这是创建一系列日期的好方法。您可以使用
combine
将
date
对象和
time
对象合并为
datetime
。我将创建以下函数：

from datetime import datetime, date

def get_showtimes(post):
    start = datetime.strptime(post['start_date'], '%Y-%m-%d')
    end = datetime.strptime(post['end_date'], '%Y-%m-%d')
    times = [datetime.strptime(t, '%I:%M %p').time() for t in post['time_list']]
    for ordinal in range(start.toordinal(), end.toordinal() + 1):
        date = date.fromordinal(date)
        for time in times:
            yield datetime.combine(date, time)

然后，在代码中，将第二个
try:except:
块及其后面的内容替换为：

try:
    showtimes = list(get_showtimes(post))
except ValueError as e:
    return Response(
        {'error': 'Time was not in a supported format. %s' % e},
        status=status.HTTP_400_BAD_REQUEST
    )

try:
    with transaction.atomic():
        for showtime in showtimes:
            show = Show.objects.create(event=event, date_time=showtime)
except IntegrityError as e:
    # etc.

我的方法有点不同。您在问号中说您正在使用
django rest框架
。。那么序列化程序在哪里呢？：）

让我们创建两个序列化程序，一个用于用户数据验证（因为我们不信任用户！），另一个用于多数据插入

我还没有检查密码！但你可以用它作为一个例子

现在，使用序列化程序，我们将验证用户数据，然后创建json数据对象：

def create_show_by_datetime(self, request):

    show_event_serializer = ShowEventSerializer(data=request.data)
    if not show_event_serializer.is_valid():
        return Response({'error': show_event_serializer.errors},status=status.HTTP_400_BAD_REQUEST)

    event_id = show_event_serializer.data['event_id']
    try:
        event = Event.objects.get(id=event_id)
    except Event.DoesNotExist:
        return Response({'error': 'event with id: %s does not exist.' % event_id},status=status.HTTP_400_BAD_REQUEST)

    start_date = show_event_serializer.data['start_date']
    end_date = show_event_serializer.data['end_date']
    time_list = show_event_serializer.data['time_list']
    date_format = '%Y-%m-%d'
    time_format = "%I:%M %p"

    try:
        datetime.strptime(start_date, date_format)
        datetime.strptime(end_date, date_format)
        for i in range(len(time_list)):
            time = datetime.strptime(time_list[i], time_format)
    except ValueError as e:
        return Response(
            {'error': 'Time was not in a supported format. %s' % e},
            status=status.HTTP_400_BAD_REQUEST
        )

    delta_days = datetime.strptime(end_date, date_format).date() - datetime.strptime(start_date, date_format).date()
    delta_days = delta_days.days + 1
    dt = None
    show_data = []
    for i in range(delta_days):
        day = datetime.strptime(start_date, date_format) + timedelta(days=i)
        for i in range(len(time_list)):
            hrs = datetime.strptime(time_list[i], time_format).hour
            mins = datetime.strptime(time_list[i], time_format).minute
            dt = day + timedelta(hours=hrs, minutes=mins)
            show_data.append({
                "event": event,
                "date_time": dt
            })

    try:
        with transaction.atomic():
            show_serializer = ShowSerializer(data=show_data, many=True)
            if show_serializer.is_valid():
                show_serializer.save()

            return Response({"data": 'Post succesfull'}, status=status.HTTP_201_CREATED)
    except IntegrityError as e:
        return Response(
            {
                'error': "event with date and time already exsits. %s-%s-%s at %s:%s" % (
                    dt.day, dt.month, dt.year, dt.hour, dt.minute),
                'detail': str(e)
            }, status=status.HTTP_400_BAD_REQUEST

因此，这段代码与您的代码基本相同，只是使用DRF保存对象的方式不同。查看
show_data
变量

这个解决方案只是另一种看待问题的方式

祝你好运


如何保存过账数据？？？没有足够的字段将数据映射到DB@Ananthu可能使用for循环？在有效负载中，您正在传递
开始日期
，
结束日期
和
时间列表
。你能解释一下为什么吗？@JerinterGeorge我已经更新了这个问题。请看一看。实际上，我还有另一种票型。每张票都应该是唯一的。这意味着每张票都与一场演出和一个座位有关。因此，我认为最好是有一个单独的节目。我已经更新了问题，请看一下。
def create_show_by_datetime(self, request):

    show_event_serializer = ShowEventSerializer(data=request.data)
    if not show_event_serializer.is_valid():
        return Response({'error': show_event_serializer.errors},status=status.HTTP_400_BAD_REQUEST)

    event_id = show_event_serializer.data['event_id']
    try:
        event = Event.objects.get(id=event_id)
    except Event.DoesNotExist:
        return Response({'error': 'event with id: %s does not exist.' % event_id},status=status.HTTP_400_BAD_REQUEST)

    start_date = show_event_serializer.data['start_date']
    end_date = show_event_serializer.data['end_date']
    time_list = show_event_serializer.data['time_list']
    date_format = '%Y-%m-%d'
    time_format = "%I:%M %p"

    try:
        datetime.strptime(start_date, date_format)
        datetime.strptime(end_date, date_format)
        for i in range(len(time_list)):
            time = datetime.strptime(time_list[i], time_format)
    except ValueError as e:
        return Response(
            {'error': 'Time was not in a supported format. %s' % e},
            status=status.HTTP_400_BAD_REQUEST
        )

    delta_days = datetime.strptime(end_date, date_format).date() - datetime.strptime(start_date, date_format).date()
    delta_days = delta_days.days + 1
    dt = None
    show_data = []
    for i in range(delta_days):
        day = datetime.strptime(start_date, date_format) + timedelta(days=i)
        for i in range(len(time_list)):
            hrs = datetime.strptime(time_list[i], time_format).hour
            mins = datetime.strptime(time_list[i], time_format).minute
            dt = day + timedelta(hours=hrs, minutes=mins)
            show_data.append({
                "event": event,
                "date_time": dt
            })

    try:
        with transaction.atomic():
            show_serializer = ShowSerializer(data=show_data, many=True)
            if show_serializer.is_valid():
                show_serializer.save()

            return Response({"data": 'Post succesfull'}, status=status.HTTP_201_CREATED)
    except IntegrityError as e:
        return Response(
            {
                'error': "event with date and time already exsits. %s-%s-%s at %s:%s" % (
                    dt.day, dt.month, dt.year, dt.hour, dt.minute),
                'detail': str(e)
            }, status=status.HTTP_400_BAD_REQUEST