NumPy参考 >例行程序 >Datetime Support Functions > numpy.datetime_as_string
numpy.
datetime_as_string
(arr, unit=None, timezone='naive', casting='same_kind')¶Convert an array of datetimes into an array of strings.
The array of UTC timestamps to format.
One of None, ‘auto’, or a datetime unit.
Timezone information to use when displaying the datetime. If ‘UTC’, end with a Z to indicate UTC time. If ‘local’, convert to the local timezone first, and suffix with a +-#### timezone offset. If a tzinfo object, then do as with ‘local’, but use the specified timezone.
Casting to allow when changing between datetime units.
An array of strings the same shape as arr.
Examples
>>> import pytz
>>> d = np.arange('2002-10-27T04:30', 4*60, 60, dtype='M8[m]')
>>> d
array(['2002-10-27T04:30', '2002-10-27T05:30', '2002-10-27T06:30',
'2002-10-27T07:30'], dtype='datetime64[m]')
Setting the timezone to UTC shows the same information, but with a Z suffix
>>> np.datetime_as_string(d, timezone='UTC')
array(['2002-10-27T04:30Z', '2002-10-27T05:30Z', '2002-10-27T06:30Z',
'2002-10-27T07:30Z'], dtype='<U35')
Note that we picked datetimes that cross a DST boundary. Passing in a
pytz
timezone object will print the appropriate offset
>>> np.datetime_as_string(d, timezone=pytz.timezone('US/Eastern'))
array(['2002-10-27T00:30-0400', '2002-10-27T01:30-0400',
'2002-10-27T01:30-0500', '2002-10-27T02:30-0500'], dtype='<U39')
Passing in a unit will change the precision
>>> np.datetime_as_string(d, unit='h')
array(['2002-10-27T04', '2002-10-27T05', '2002-10-27T06', '2002-10-27T07'],
dtype='<U32')
>>> np.datetime_as_string(d, unit='s')
array(['2002-10-27T04:30:00', '2002-10-27T05:30:00', '2002-10-27T06:30:00',
'2002-10-27T07:30:00'], dtype='<U38')
‘casting’ can be used to specify whether precision can be changed
>>> np.datetime_as_string(d, unit='h', casting='safe')
Traceback (most recent call last):
...
TypeError: Cannot create a datetime string as units 'h' from a NumPy
datetime with units 'm' according to the rule 'safe'