# [SciPy-user] Numpy for Matlab users

Nils Wagner nwagner at mecha.uni-stuttgart.de
Thu Feb 16 02:14:42 CST 2006

Robert Kern wrote:
>Nils Wagner wrote:
>
>>Robert Kern wrote:
>>
>>
>>>Nils Wagner wrote:
>>>
>>>
>>>>This might be straightforward if I want to remove the first or last row.
>>>>
>>>>a=a[1:,:]
>>>>a=a[:3,:]
>>>>
>>>>but how can I efficiently remove the second or third row w.r.t. to your
>>>>example ?
>>>>
>>>>
>>>Robert Cimrman gave you the answer.
>>>
>>>
>>>>>a=rand(4,3)
>>>>>a
>>>>>
>>array([[ 0.91343331,  0.78947381,  0.39115252],
>>       [ 0.17682632,  0.75310694,  0.0081875 ],
>>       [ 0.82873565,  0.08136179,  0.46704486],
>>       [ 0.38479685,  0.54347342,  0.21294132]])
>>
>>
>>>>>a=a[(0,2,3),:]
>>>>>a
>>>>>
>>array([[ 0.91343331,  0.78947381,  0.39115252],
>>       [ 0.82873565,  0.08136179,  0.46704486],
>>       [ 0.38479685,  0.54347342,  0.21294132]])
>>
>>But it might be easier to say what I would like to remove instead of
>>what I want to keep ...
>>
>>Do you agree ?
>>
>
>Sure. Think about lists and the .remove() method. Then you can wrap it into a
>function to make it convenient.
>
>
It's a one-liner in Matlab.
A[i,:] = []
Is numpy competitive w.r.t. this task ;-)   ?

Nils