Re: numpy array question

2020-04-02 Thread Peter Otten
jagmit sandhu wrote: > python newbie. I can't understand the following about numpy arrays: > > x = np.array([[0, 1],[2,3],[4,5],[6,7]]) > x > array([[0, 1], >[2, 3], >[4, 5], >[6, 7]]) > x.shape > (4, 2) > y = x[:,0] > y > array([0, 2, 4, 6]) > y.shape > (4,) > > Why is t

Re: numpy array question

2020-04-02 Thread edmondo . giovannozzi
Il giorno giovedì 2 aprile 2020 06:30:22 UTC+2, jagmit sandhu ha scritto: > python newbie. I can't understand the following about numpy arrays: > > x = np.array([[0, 1],[2,3],[4,5],[6,7]]) > x > array([[0, 1], >[2, 3], >[4, 5], >[6, 7]]) > x.shape > (4, 2) > y = x[:,0] > y

Re: numpy array - convert hex to int

2019-09-10 Thread Piet van Oostrum
Sharan Basappa writes: > On Sunday, 8 September 2019 11:16:52 UTC-4, Luciano Ramalho wrote: >> >>> int('C0FFEE', 16) >> 12648430 >> >> There you go! >> >> On Sun, Sep 8, 2019 at 12:02 PM Sharan Basappa >> wrote: >> > >> > I have a numpy array that has data in the form of hex. >> > I would li

Re: numpy array - convert hex to int

2019-09-09 Thread Sharan Basappa
On Sunday, 8 September 2019 11:16:52 UTC-4, Luciano Ramalho wrote: > >>> int('C0FFEE', 16) > 12648430 > > There you go! > > On Sun, Sep 8, 2019 at 12:02 PM Sharan Basappa > wrote: > > > > I have a numpy array that has data in the form of hex. > > I would like to convert that into decimal/integ

Re: numpy array - convert hex to int

2019-09-08 Thread Luciano Ramalho
>>> int('C0FFEE', 16) 12648430 There you go! On Sun, Sep 8, 2019 at 12:02 PM Sharan Basappa wrote: > > I have a numpy array that has data in the form of hex. > I would like to convert that into decimal/integer. > Need suggestions please. > -- > https://mail.python.org/mailman/listinfo/python-lis

Re: Numpy array

2018-05-21 Thread Rob Gaddi
On 05/18/2018 09:50 PM, Sharan Basappa wrote: This is regarding numpy array. I am a bit confused how parts of the array are being accessed in the example below. 1 import scipy as sp 2 data = sp.genfromtxt("web_traffic.tsv", delimiter="\t") 3 print(data[:10]) 4 x = data[:,0] 5 y = data[:,1] App

Re: Numpy array

2018-05-20 Thread Gary Herron
The "indexing" page of the documentation might help you with this: https://docs.scipy.org/doc/numpy-1.14.0/reference/arrays.indexing.html On 05/18/2018 09:50 PM, sharan.basa...@gmail.com wrote: This is regarding numpy array. I am a bit confused how parts of the array are being accessed in the

Re: numpy array product driving me mad

2015-03-20 Thread Mr. Twister
>> I think that you want >> >> P * R[;,None] > > Sorry, I meant > > P * R[:, None] > > Manolo Muchísimas gracias, Manolo. Eres un genio y me has ayudado mucho. Te debo una. -- https://mail.python.org/mailman/listinfo/python-list

Re: numpy array product driving me mad

2015-03-20 Thread Manolo Martínez
On 03/20/15 at 02:11pm, Manolo Martínez wrote: > On 03/20/15 at 01:46pm, Mr. Twister wrote: > > > I have two numpy arrays: [...] > > Is there a direct, single expression command to get this result? > > I think that you want > > P * R[;,None] Sorry, I meant P * R[:, None] Manolo

Re: numpy array product driving me mad

2015-03-20 Thread Manolo Martínez
On 03/20/15 at 01:46pm, Mr. Twister wrote: > I have two numpy arrays: > > >>> P > array([[[ 2, 3], > [33, 44], > [22, 11], > [ 1, 2]]]) > >>> R > array([0, 1, 2, 3]) > > the values of these may of course be different. The important fact is that: > > >>> P.shape > (1,

Re: Numpy Array of Sets

2014-05-25 Thread LJ
Thank you very much! -- https://mail.python.org/mailman/listinfo/python-list

Re: Numpy Array of Sets

2014-05-25 Thread Peter Otten
LJ wrote: > Thank you for the reply. > > So, as long as I access and modify the elements of, for example, > > A=array([[set([])]*4]*3) > > > as (for example): > > a[0][1] = a[0][1] | set([1,2]) > > or: > > a[0][1]=set([1,2]) > > then I should have no problems? As long as you set (i. e. re

Re: Numpy Array of Sets

2014-05-25 Thread LJ
Thank you for the reply. So, as long as I access and modify the elements of, for example, A=array([[set([])]*4]*3) as (for example): a[0][1] = a[0][1] | set([1,2]) or: a[0][1]=set([1,2]) then I should have no problems? -- https://mail.python.org/mailman/listinfo/python-list

Re: Numpy Array of Sets

2014-05-25 Thread Peter Otten
LJ wrote: > Wolfgang, thank you very much for your reply. > > Following the example in the link, the problem appears: > A = [[0]*2]*3 You can see this as a shortcut for value = 0 inner = [value, value] A = [inner, inner, inner] When the value is mutable (like your original set) a modific

Re: Numpy Array of Sets

2014-05-25 Thread LJ
Wolfgang, thank you very much for your reply. Following the example in the link, the problem appears: >>> A = [[0]*2]*3 >>> A [[0, 0], [0, 0], [0, 0]] >>> A[0][0] = 5 >>> A [[5, 0], [5, 0], [5, 0]] Now, if I use a numpy array: >>> d=array([[0]*2]*3) >>> d array([[0, 0], [0, 0], [0

Re: Numpy Array of Sets

2014-05-24 Thread Wolfgang Maier
On 25.05.2014 00:14, Robert Kern wrote: On 2014-05-24 23:05, Luis José Novoa wrote: Hi All, Hope you're doing great. One quick question. I am defining an array of sets using numpy as: a=array([set([])]*3) Has nothing to do with numpy, but the problem is exclusively with your innermost expr

Re: Numpy Array of Sets

2014-05-24 Thread Robert Kern
On 2014-05-24 23:05, Luis José Novoa wrote: Hi All, Hope you're doing great. One quick question. I am defining an array of sets using numpy as: a=array([set([])]*3) Now, if I want to add an element to the set in, lets say, a[0], and I use the .add(4) operation, which results in: array([set(

Re: numpy array operation

2013-01-29 Thread Terry Reedy
On 1/29/2013 1:49 PM, Alok Singhal wrote: On Tue, 29 Jan 2013 00:41:54 -0800, C. Ng wrote: Is there a numpy operation that does the following to the array? 1 2 ==> 4 3 3 4 2 1 Thanks in advance. How about: import numpy as np a = np.array([[1,2],[3,4]]) a array([[1, 2], [3, 4]])

Re: numpy array operation

2013-01-29 Thread Alok Singhal
On Tue, 29 Jan 2013 00:41:54 -0800, C. Ng wrote: > Is there a numpy operation that does the following to the array? > > 1 2 ==> 4 3 > 3 4 2 1 > > Thanks in advance. How about: >>> import numpy as np >>> a = np.array([[1,2],[3,4]]) >>> a array([[1, 2], [3, 4]]) >>> a[::-1, ::-1]

Re: numpy array operation

2013-01-29 Thread Tim Williams
On Tuesday, January 29, 2013 3:41:54 AM UTC-5, C. Ng wrote: > Is there a numpy operation that does the following to the array? > > > > 1 2 ==> 4 3 > > 3 4 2 1 > > > > Thanks in advance. >>> import numpy as np >>> a=np.array([[1,2],[3,4]]) >>> a array([[1, 2], [3, 4]]) >>> np.

Re: numpy array operation

2013-01-29 Thread Peter Otten
C. Ng wrote: > Is there a numpy operation that does the following to the array? > > 1 2 ==> 4 3 > 3 4 2 1 How about >>> a array([[1, 2], [3, 4]]) >>> a[::-1].transpose()[::-1].transpose() array([[4, 3], [2, 1]]) Or did you mean >>> a.reshape((4,))[::-1].reshape((2,2)) ar

Re: numpy array merge

2009-08-10 Thread Robert Kern
On 2009-08-10 17:38, Nathan wrote: Is there an easy way to merge two numpy arrays with different rank sizes (terminology?). You will want to ask numpy questions on the numpy mailing list. http://www.scipy.org/Mailing_Lists I believe that "shape" is the term you are looking for. I want to

Re: numpy array sorting weirdness

2009-03-29 Thread Daniel Fetchinson
>> Is there any reason the 'axis' keyword argument doesn't default to the >> value that corresponds to python list behaviour? That would make lot >> of sense I think. Or retaining compatibility with python lists is not >> really a goal of numpy.array? > > Not at all. It's an entirely different data

Re: numpy array sorting weirdness

2009-03-29 Thread Robert Kern
On 2009-03-28 22:35, Daniel Fetchinson wrote: Is there any reason the 'axis' keyword argument doesn't default to the value that corresponds to python list behaviour? That would make lot of sense I think. Or retaining compatibility with python lists is not really a goal of numpy.array? Not at al

Re: numpy array sorting weirdness

2009-03-28 Thread Daniel Fetchinson
>> The fact that the following two outputs are not the same is a bug or a >> feature of numpy? >> >> # I would have thought the two array outputs would be the same ## >> >> import numpy >> >> a = [ [ 0, 0 ], [ 1, 0 ], [ 1, 1 ] ] >> >> pythonarray = a >> pythonarray.sort( ) >> print pythonar

Re: numpy array sorting weirdness

2009-03-28 Thread John O'Hagan
On Sun, 29 Mar 2009, Daniel Fetchinson wrote: [...] > The fact that the following two outputs are not the same is a bug or a > feature of numpy? > > # I would have thought the two array outputs would be the same ## > > import numpy > > a = [ [ 0, 0 ], [ 1, 0 ], [ 1, 1 ] ] > > pythonarray

Re: numpy array sorting weirdness

2009-03-28 Thread MRAB
Daniel Fetchinson wrote: So far I was working under the assumption that the numpy array implementation can be used as a drop-in replacement for native python lists, i.e. wherever I see a list 'a' and I want to speed up my numerical calculations I just replace it with 'numpy.array( a )' and everyt

Re: numpy array sorting weirdness

2009-03-28 Thread Daniel Fetchinson
>> So far I was working under the assumption that the numpy array >> implementation can be used as a drop-in replacement for native python >> lists, i.e. wherever I see a list 'a' and I want to speed up my >> numerical calculations I just replace it with 'numpy.array( a )' and >> everything will wo

Re: Numpy array to gzip file

2008-06-11 Thread Robert Kern
Sean Davis wrote: I have a set of numpy arrays which I would like to save to a gzip file. Here is an example without gzip: b=numpy.ones(100,dtype=numpy.uint8) a=numpy.zeros(100,dtype=numpy.uint8) fd = file('test.dat','wb') a.tofile(fd) b.tofile(fd) fd.close() This works fine. However,

Re: Numpy array to gzip file

2008-06-11 Thread Sean Davis
On Jun 11, 12:42 pm, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote: > On Jun 11, 9:17 am, Sean Davis <[EMAIL PROTECTED]> wrote: > > > > > I have a set of numpy arrays which I would like to save to a gzip > > file. Here is an example without gzip: > > > b=numpy.ones(100,dtype=numpy.uint8) > > a

Re: Numpy array to gzip file

2008-06-11 Thread [EMAIL PROTECTED]
On Jun 11, 9:17 am, Sean Davis <[EMAIL PROTECTED]> wrote: > I have a set of numpy arrays which I would like to save to a gzip > file. Here is an example without gzip: > > b=numpy.ones(100,dtype=numpy.uint8) > a=numpy.zeros(100,dtype=numpy.uint8) > fd = file('test.dat','wb') > a.tofile(fd)

Re: Numpy array index handling

2007-07-13 Thread Robert Kern
sturlamolden wrote: > Enthought and similar distros are in my experience "unclean". They > don't always work and they are difficult to update. I rather download > the binary installers (for Windows) and install the packages I need. Right, that's why we (I'm an Enthought employee) haven't been upda

Re: Numpy array index handling

2007-07-13 Thread Robert Kern
[EMAIL PROTECTED] wrote: > Thanks a lot for your reply. > I'll have a look at the numpy-discussion for future issues. > > FYI, I'm using Python 2.4.3 for Windows (Enthought Edition) and the > included IPython shell. I found my mistake; importing of pylab. > E.g., this works > from pylab import * ;

Re: Numpy array index handling

2007-07-13 Thread sturlamolden
On 13 Jul, 22:52, [EMAIL PROTECTED] wrote: > It seems a bit risky to use 'from scipy import *'. Maybe it's better > to use 'import scipy' and then scipy.arange, to be sure what is > actually being used? Would there be any disadvanages with that > approach, other than more use of the keyboard? Gen

Re: Numpy array index handling

2007-07-13 Thread phishboh
Thanks a lot for your reply. I'll have a look at the numpy-discussion for future issues. FYI, I'm using Python 2.4.3 for Windows (Enthought Edition) and the included IPython shell. I found my mistake; importing of pylab. E.g., this works from pylab import * ; from scipy import * ; y = arange(3) ;

Re: Numpy array index handling

2007-07-13 Thread sturlamolden
>>> from numpy import * >>> from numpy.random import * >>> N = 100 >>> input = sign(randn(N)) >>> a = arange(N) >>> output = zeros(N) >>> output[input < 0] = 10 * a[input < 0] >>> output[input > 0] = 20 * a[input > 0] >>> Worked fine for me. S.M. -- http://mail.python.org/mailman/list

Re: Numpy array index handling

2007-07-13 Thread Robert Kern
[EMAIL PROTECTED] wrote: > Being a Matlab user wanting to switch to Python/SciPy, Fantastic! You might be interested in joining the numpy mailing list. There are a lot more of us numpy devs and users there than here. http://www.scipy.org/Mailing_Lists > I'd like to > know how the following Mat