Question

是否可以转换此类内容;

array([datetime.datetime(2014, 2, 1, 0, 0, 0, 100000),
       datetime.datetime(2014, 2, 1, 0, 0, 0, 300000),
       datetime.datetime(2014, 2, 1, 0, 0, 0, 500000), ...,
       datetime.datetime(2014, 2, 1, 19, 30, 0, 500000),
       datetime.datetime(2014, 2, 1, 19, 30, 0, 700000),
       datetime.datetime(2014, 2, 1, 19, 30, 0, 900000)], dtype=object)

到此：

array([  1.39277301e+09,   1.39277301e+09,   1.39277301e+09, ...,
         1.39285442e+09,   1.39285442e+09,   1.39285442e+09])

我基本上想将datetime.datetime转换为timestamp，dtype = float。

Answer 1

这样的事情怎么样：

（Python 2.x）：

"MMM DD, YYYY"

对于Python 3.x：

import datetime

temp_array = numpy.array([(i - datetime.datetime(1970, 1, 1)).total_seconds() for i in old_array])
new_array = temp_array.astype('float')

Answer 2

获得public void ClearHistory() => FrameFacade.BackStack.Clear();的最佳方法是将timestamp中的纪元减去：

<强>代码：

datetime

<强>结果：

import datetime as dt

times = np.array([
    dt.datetime(2014, 2, 1, 0, 0, 0, 100000),
    dt.datetime(2014, 2, 1, 0, 0, 0, 300000),
    dt.datetime(2014, 2, 1, 0, 0, 0, 500000),
])

# get a datetime that is equal to epoch
epoch = dt.datetime(1970, 1, 1)

for t in [(d - epoch).total_seconds() for d in times]:
    print('%.6f' % t)

Answer 3

mktime()会转换为时间戳，但似乎会失去超过秒的准确度。

>>> import datetime
>>> from time import mktime

>>> x = datetime.datetime.now()
>>> y = mktime(x.timetuple())
>>> print(y)
1493096455.0

>>> type(y)
<type 'float'>

>>> z = y/1000000000
>>> print(z)
1.493096455

Answer 4

In [475]: x
Out[475]: 
array([datetime.datetime(2014, 2, 1, 0, 0, 0, 100000),
       datetime.datetime(2014, 2, 1, 0, 0, 0, 300000),
       datetime.datetime(2014, 2, 1, 0, 0, 0, 500000),
       datetime.datetime(2014, 2, 1, 19, 30, 0, 500000),
       datetime.datetime(2014, 2, 1, 19, 30, 0, 700000),
       datetime.datetime(2014, 2, 1, 19, 30, 0, 900000)], dtype=object)
In [476]: x.astype('datetime64[us]')
Out[476]: 
array(['2014-02-01T00:00:00.100000', '2014-02-01T00:00:00.300000',
       '2014-02-01T00:00:00.500000', '2014-02-01T19:30:00.500000',
       '2014-02-01T19:30:00.700000', '2014-02-01T19:30:00.900000'], dtype='datetime64[us]')

每个都保存为8字节的浮点数，被解释为日期时间。

In [477]: _.dtype
Out[477]: dtype('<M8[us]')
In [478]: __.itemsize
Out[478]: 8

您可以更改单位（年，日等）;做数学等

In [479]: x1=x.astype('datetime64[us]')
In [480]: np.diff(x1)
Out[480]: array([     200000,      200000, 70200000000,      200000,      200000], dtype='timedelta64[us]')

将数组datatime.datetime转换为float

4 个答案: