如何比較兩個日期Numpy.datetime64

Question

什麼是比較兩個numpy.datetime64的日期部分的正確方法？

A: 2011-01-10 Type: <type 'numpy.datetime64'> 
B: 2011-01-10T09:00:00.000000-0700 Type: <type 'numpy.datetime64'> 

以上例子將通過指定「datetime64 [d]」數據類型比較之前

Answer 1

您會想要去除的時間信息datetime64返回false通過比較（A == B），像這樣：

>>> a = numpy.datetime64('2011-01-10') 
>>> b = numpy.datetime64('2011-01-10T09:00:00.000000-0700') 
>>> a == b 
False 
>>> a.astype('datetime64[D]') == b.astype('datetime64[D]') 
True 

我不能讓numpy的創建datetime64[D]值從你給上面b，順便把字符串數組。我得到這個錯誤：

>>> b = numpy.array(['2011-01-10T09:00:00.000000-0700'], dtype='datetime64[D]') 
TypeError: Cannot parse "2011-01-10T09:00:00.000000-0700" as unit 'D' using casting rule 'same_kind'