[Numpy-discussion] array manupulation

[Bryan Van de Ven]

I'm not sure what you tried, but stack will do what you are seeking:

In [7]: cc = np.ones((2,10)) * np.arange(1, 11)

In [8]: cc
Out[8]: 
array([[  1.,   2.,   3.,   4.,   5.,   6.,   7.,   8.,   9.,  10.],
       [  1.,   2.,   3.,   4.,   5.,   6.,   7.,   8.,   9.,  10.]])

In [9]: np.vstack((np.zeros(10), cc))
Out[9]: 
array([[  0.,   0.,   0.,   0.,   0.,   0.,   0.,   0.,   0.,   0.],
       [  1.,   2.,   3.,   4.,   5.,   6.,   7.,   8.,   9.,  10.],
       [  1.,   2.,   3.,   4.,   5.,   6.,   7.,   8.,   9.,  10.]])

Bryan


On May 25, 2013, at 7:19 AM, Sudheer Joseph <sudheer.joseph at yahoo.com> wrote:

> Dear experts,
> I can do below operation in matlab but I wanted to do the same in python numpy array.
> I tried np.vstak  and np.concatenate but not getting the desired results. please help. I wanted to add a row of zeros to the beginning of a numpy array. What is  the available quick way. 
> 
>>> cc=[1:10;1:10]
> 
> cc =
>      1     2     3     4     5     6     7     8     9    10
>      1     2     3     4     5     6     7     8     9    10
>>> cc=[cc(1,:)*0;cc]
> cc =
>      0     0     0     0     0     0     0     0     0     0
>      1     2     3     4     5     6     7     8     9    10
>      1     2     3     4     5     6     7     8     9    10
> 
> wit best regards,
> Sudheer 
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