numpy.datetime_as_string#

numpy.datetime_as_string(arr, unit=None, timezone='naive', casting='same_kind')#

将日期时间数组转换为字符串数组.

参数:
arr类数组的 datetime64

要格式化的UTC时间戳数组.

unitstr

None、’auto’ 或一个 datetime 单位 之一.

timezone{‘naive’, ‘UTC’, ‘local’} 或 tzinfo

显示日期时间时要使用的时间信息.如果是’UTC’,则以Z结尾表示UTC时间.如果是’local’,则先转换为本地时区,并后缀一个+-####时区偏移.如果是tzinfo对象,则与’local’一样处理,但使用指定时区.

casting{‘no’, ‘equiv’, ‘safe’, ‘same_kind’, ‘unsafe’}

在日期时间单位之间转换时允许的转换.

返回:
str_arrndarray

与 arr 形状相同的字符串数组.

示例

>>> import numpy as np
>>> 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]')

将时区设置为UTC显示相同的信息,但带有Z后缀

>>> 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')

请注意,我们选择了跨越夏令时边界的日期时间.传入一个 pytz 时区对象将打印适当的偏移量.

>>> 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')

传入一个单位将改变精度

>>> 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’ 可以用来指定精度是否可以改变

>>> 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'
On this page