转换为日期的正确方法

看看 dateutil.parse datetime

from dateutil.parser import parse

def is_date(object):
    try:
        #Check if it's a date of any format.
        parse(object)
        return 'Valid until formated_date'
    except ValueError:
        #When cannot be a date
        return '2 year warranty'

要将第一个结果转换为DateTime对象,请使用->

import datetime

date_object = datetime.datetime.strptime("2019-12-20T08:59:49.897Z", '%Y-%m-%dT%H:%M:%S.%fZ')
temp_date = date_object.date() # returns date
# then convert to date.
str(temp_date) # result '2019-12-20'

相反,我们必须使用strptime方法,它在稍微修改字符串后接受一个字符串和一个格式化字符串。我假设我们希望datetime对象保留时区信息,以便稍后可以在所选时区中输出datetime,但不幸的是,strTime将不接受Z说明符(因此需要修改字符串)。

def process_datestring(my_date_string):

    # In Python 3, a UTC class exists
    import datetime
    try:
        from datetime import timezone
        utc = timezone.utc
    except ImportError:
        # Python 2
        class UTC(datetime.tzinfo):
            def utcoffset(self, dt):
                return datetime.timedelta(0)

            def tzname(self, dt):
                return "UTC"

            def dst(self, dt):
                return datetime.timedelta(0)
    utc = UTC()

    # If we have a Z-terminated datetime string,
    # trim off the Z and build a UTC datetime object
    if my_date_string and my_date_string[-1] == 'Z':
        my_datetime = datetime.datetime.strptime(
            my_date_string[:-1], '%Y-%m-%dT%H:%M:%S.%f')
        my_datetime.replace(tzinfo=UTC())
        # Use this newly-created datetime object as you see fit
        return 'Valid until formated_date'

    # Otherwise, test for a simple date

    try:
        # Convert a string of form YYYY-MM-DD to a datetime object
        my_datetime = datetime.datetime.strptime(
             my_date_string, '%Y-%m-%d')
        # This datetime object is naive - it is NOT timezone aware
        return 'Valid until formated_date'
    except ValueError:
        # Unable to convert this string - perhaps it is a number?
        try:
            # This will raise an exception if my_date_string is not
            # a simple number
            float(my_date_string)
            return '2 years warranty'
        except ValueError:
            # Not a number either; most likely an unhandled date format.
            raise ValueError('Unhandled string!')

my_date_string = "2019-12-20T08:59:49.897Z"
print(process_datestring(my_date_string))
# returns 'Valid until formated_date'
my_date_string = "2019-12-20"
print(process_datestring(my_date_string))
# returns 'Valid until formated_date'
my_date_string = "3"
print(process_datestring(my_date_string))
# returns '2 years warranty'
my_date_string = "test"
print(process_datestring(my_date_string))
# raises ValueError 'Unhandled string!'

您也可以尝试下面的代码。

from datetime import datetime

def is_date(s):
    try:
        d = datetime.strptime(s, "%Y-%m-%dT%H:%M:%S.%fZ")   

        if type(d) is datetime:
            return True
        else:
            return False
    except:
        return False

s = "2019-12-20T08:59:49.897Z"
print(is_date(s)) # True

s2 = "2019-12-20T08:59"
print(is_date(s2)) # False

在Python的交互式控制台上理解上述内容的步骤:

>>> from datetime import datetime
>>>
>>> s = "2019-12-20T08:59:49.897Z"
>>> type(s)
<class 'str'>
>>>
>>> d = datetime.strptime(s, "%Y-%m-%dT%H:%M:%S.%fZ")
>>> d
datetime.datetime(2019, 12, 20, 8, 59, 49, 897000)
>>>
>>> type(d)
<class 'datetime.datetime'>
>>>
>>> type(d) is datetime
True
>>>
>>> type(d) is str
False
>>>
>>> type(d) is int
False
>>>
>>> type(d) is list
False
>>>
>>> type(d) is tuple
False
>>>
>>> type(d) is dict
False
>>>
>>> type(d) is float
False
>>>
>>> type(d) is complex
False
>>>

有一个旧的图书馆,它的功能正是你想要的 iso8601 python-dateutil 还将解析ISO8601字符串和更多字符串。