[Numpy-discussion] numpy sort is not working

Jadhav, Alok alok.jadhav@credit-suisse....
Tue Sep 11 00:52:57 CDT 2012


Hi Travis,

 

Very Strange. I am on version 1.6.2 L

What could I be missing. I started using numpy quite recently. Is there
a way to share the data with you?

 

Regards,

 

Alok Jadhav

GAT IT Hong Kong

+852 2101 6274 (*852 6274)

 

From: numpy-discussion-bounces@scipy.org
[mailto:numpy-discussion-bounces@scipy.org] On Behalf Of Travis Oliphant
Sent: Tuesday, September 11, 2012 11:58 AM
To: Discussion of Numerical Python
Subject: Re: [Numpy-discussion] numpy sort is not working

 

Hey Alok, 

 

This is worth taking a look.   What version of NumPy are you using?  

 

It is not related directly to the issue you referenced as that was an
endian-ness issue and your data is native-order.   

 

Your example seems to work for me (with a simulated case on 1.6.1)

 

Best,

 

-Travis

 

 

On Sep 10, 2012, at 10:46 PM, Jadhav, Alok wrote:





 

Hi everyone,

 

I have a numpy array of dimensions

 

>>> allRics.shape 
(583760, 1) 

 

To sort the array, I set the dtype of the array as follows:

 

allRics.dtype = [('idx', np.float), ('opened', np.float), ('time',
np.float),('trdp1',np.float),('trdp0',np.float),('dt',np.float),('value'
,np.float)] 

>>> allRics.dtype

dtype([('idx', '<f8'), ('opened', '<f8'), ('time', '<f8'), ('trdp1',
'<f8'), ('trdp0', '<f8'), ('dt', '<f8'), ('value', '<f8')])

 

I checked and the endianness in dtype is correct.

 

When I sort the array, the output array of sort is same as original
array without any change. I want to sort the allRics numpy array on
'time'. I do the following.

 

>>> x=np.sort(allRics,order='time')

>>> x[17330:17350]['time']

array([[ 61184.4  ],

       [ 61188.51 ],

       [ 61188.979],

       [ 61188.979],

       [ 61189.989],

       [ 61191.66 ],

       [ 61194.35 ],

       [ 61194.35 ],

       [ 61198.79 ],

       [ 61198.145],

       [ 36126.217],

       [ 36126.217],

       [ 36126.218],

       [ 36126.218],

       [ 36126.219],

       [ 36126.271],

       [ 36126.271],

       [ 36126.271],

       [ 36126.293],

       [ 36126.293]])

 

Time column doesn't change its order. Could someone please advise what
is missing here? Is this related to the bug

http://www.mail-archive.com/numpy-discussion@scipy.org/msg23060.html
(from 2010).

 

Regards,

Alok

 

 

 

 

 

Alok Jadhav

CREDIT SUISSE AG

GAT IT Hong Kong, KVAG 67

International Commerce Centre | Hong Kong | Hong Kong

Phone +852 2101 6274 | Mobile +852 9169 7172

alok.jadhav@credit-suisse.com | www.credit-suisse.com
<http://www.credit-suisse.com/> 

 

 

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