numpy的recordarray与时间？

Question

我正在尝试将XML文件读入NumPy记录数组。时间以祖鲁时间为准，u'2013-06-06T17:47:38Z'其他列为floats。时间和floats都可以转换为NumPy数组。但是，如果我尝试制作一个recordarray，它会以多种方式失败（这可能表明我不知道如何创建记录数组）：In [124]: dataarr = np.array(zip(*[datadict[k] for k in keys]),   .....:                     dtype=[(k,dtypes[k]) for k in keys])Traceback (most recent call last):  File "<ipython-input-124-d59123796cfa>", line 2, in <module>    dtype=[(k,dtypes[k]) for k in keys])ValueError: Cannot create a NumPy datetime other than NaT with generic unitsIn [125]: dataarr = np.array([datadict[k] for k in keys],                    dtype=[(k,dtypes[k]) for k in keys])Traceback (most recent call last):  File "<ipython-input-125-ee9077bf1961>", line 2, in <module>    dtype=[(k,dtypes[k]) for k in keys])TypeError: expected a readable buffer objectIn [126]: dataarr = np.array([datadict[k] for k in keys],                    dtype=[dtypes[k] for k in keys])Traceback (most recent call last):  File "<ipython-input-126-a456052bdfd4>", line 2, in <module>    dtype=[dtypes[k] for k in keys])TypeError: data type not understoodIn [127]: dtypesOut[127]: {'altitude': 'float', 'distance': 'float', 'time': 'datetime64'}创建recordarray收录时间的正确方法是什么？（keys是一个列表，datadict并且dtype是http://stardict.sourceforge.net/Dictionaries.php下载）

Answer 1

糟糕，在recarray中使用numpy datetime64弄清楚了

我尝试使用datetime[D]，但失败了：

In [19]: dtypes

Out[19]: {'altitude': 'float', 'distance': 'float', 'time': 'datetime64[D]'}

In [20]: dataarr = np.array(zip(*[datadict[k] for k in keys]),

                    dtype=[(k,dtypes[k]) for k in keys])

Traceback (most recent call last):

  File "<ipython-input-20-d59123796cfa>", line 2, in <module>

    dtype=[(k,dtypes[k]) for k in keys])

TypeError: Cannot cast NumPy timedelta64 scalar from metadata [s] to [D] according to the rule 'same_kind'

但datetime[s]有效：

In [22]: dtypes

Out[22]: {'altitude': 'float', 'distance': 'float', 'time': 'datetime64[s]'}

In [23]: dataarr = np.array(zip(*[datadict[k] for k in keys]),

                    dtype=[(k,dtypes[k]) for k in keys])