使用 strptime 时忽略日期时间戳中未转换的数据

Question

第三方 API returns 我的 CSV 数据包含这样的日期时间戳：

dtval = '2016-10-14 05:09:30+00:00'

我必须将其转换为以下格式：mm/dd/yyyy。

这里我不确定指令的最后 +XX:XX:

datetime.datetime.strptime(dtval, "%Y-%m-%d %H:%M:%S+XX:XX").strftime('%m/%d/%Y')

我尝试了以下但没有成功：

>>>datetime.datetime.strptime('2016-10-14 05:09:30+00:00', '%Y-%m-%d %H:%M:%S')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.5/_strptime.py", line 500, in _strptime_datetime
    tt, fraction = _strptime(data_string, format)
  File "/usr/lib/python3.5/_strptime.py", line 340, in _strptime
    data_string[found.end():])
ValueError: unconverted data remains: +00:00


>>>datetime.datetime.strptime('2016-10-14 05:09:30+00:00', "%Y-%m-%d %H:%M:%S%z")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.5/_strptime.py", line 500, in _strptime_datetime
    tt, fraction = _strptime(data_string, format)
  File "/usr/lib/python3.5/_strptime.py", line 337, in _strptime
    (data_string, format))
ValueError: time data '2016-10-14 05:09:30+00:00' does not match format '%Y-%m-%d %H:%M:%S+%z'

Python3.4+ 的 datetime 模块中是否有忽略剩余未转换数据的选项？

我检查了 this 但没有找到任何这样的选项

Answer 1

经过一些研究，我在 django 的源代码中找到了这个修复程序：

class FixedOffset(tzinfo):
    """
    Fixed offset in minutes east from UTC. Taken from Python's docs.
    Kept as close as possible to the reference version. __init__ was changed
    to make its arguments optional, according to Python's requirement that
    tzinfo subclasses can be instantiated without arguments.
    """

    def __init__(self, offset=None, name=None):
        if offset is not None:
            self.__offset = timedelta(minutes=offset)
        if name is not None:
            self.__name = name

    def utcoffset(self, dt):
        return self.__offset

    def tzname(self, dt):
        return self.__name

    def dst(self, dt):
        return timedelta(0)
    def get_timezone(offset):
        """
        Returns a tzinfo instance with a fixed offset from UTC.
        """
        if isinstance(offset, timedelta):
            offset = offset.seconds // 60
        sign = '-' if offset < 0 else '+'
        hhmm = '%02d%02d' % divmod(abs(offset), 60)
        name = sign + hhmm
        return FixedOffset(offset, name)


def custom_strptime(self, value):
    """Parses a string and return a datetime.datetime.
    This function supports time zone offsets. When the input contains one,
    the output uses a timezone with a fixed offset from UTC.
    Raises ValueError if the input is well formatted but not a valid datetime.
    Returns None if the input isn't well formatted.
    """
    datetime_re = re.compile(
        r'(?P<year>\d{4})-(?P<month>\d{1,2})-(?P<day>\d{1,2})'
        r'[T ](?P<hour>\d{1,2}):(?P<minute>\d{1,2})'
        r'(?::(?P<second>\d{1,2})(?:\.(?P<microsecond>\d{1,6})\d{0,6})?)?'
        r'(?P<tzinfo>Z|[+-]\d{2}(?::?\d{2})?)?$'
    )
    match = datetime_re.match(value)
    if match:
        kw = match.groupdict()
        if kw['microsecond']:
            kw['microsecond'] = kw['microsecond'].ljust(6, '0')
        tzinfo = kw.pop('tzinfo')
        if tzinfo == 'Z':
            tzinfo = utc
        elif tzinfo is not None:
            offset_mins = int(tzinfo[-2:]) if len(tzinfo) > 3 else 0
            offset = 60 * int(tzinfo[1:3]) + offset_mins
            if tzinfo[0] == '-':
                offset = -offset
            tzinfo = get_timezone(offset)
            kw = {k: int(v) for k, v in kw.items() if v is not None}

        kw['tzinfo'] = tzinfo
        return datetime.datetime(**kw)

使用 strptime 时忽略日期时间戳中未转换的数据

Ignore unconverted data from date-time stamp when using strptime

python-3.5

strptime