Hi,
I am really confused on the np array or record array, and cannot understand how it works.
What I want to do is that I have a normal python two dimensional array/list:
a = [['2000-01-01', 2],['2000-01-02', 3]]
I want to convert it to a recarray with this dtype [('date', 'object'), ('count', 'int')]. I tried multiple ways and none of them works. And some of the tests show pretty odd behavior.
This is good, and it is almost what i want:
>>> import numpy as np
>>> a = [('2000-01-01', 2), ('2000-01-02', 3)]
>>> np.array(a, dtype=[('date', 'object'), ('count', 'int')])
array([('2000-01-01', 2), ('2000-01-02', 3)],
dtype=[('date', '|O8'), ('count', '<i8')])
Why this doesn't work?!
>>> a = [['2000-01-01', 2],['2000-01-02', 3]]
>>> np.array(a, dtype=[('date', 'object'), ('count', 'int')])
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ValueError: tried to set void-array with object members using buffer.
Why can this cause segmentation fault?!
>>> a = [['2000-01-01', 2],['2000-01-02', 3]]
>>> np.ndarray((len(a),), buffer=np.array(a), dtype=[('date', 'object'), ('count', 'int')])
Segmentation fault (And python quit!)
Python version 2.6.5
>>> x = np.array([(1,2),(3,4)])
>>> x
array([[1, 2],
[3, 4]])
>>> np.array([[1, 2], [3, 4]])
array([[1, 2],
[3, 4]])
Can anyone help me about this?
Thanks.