Hello, Thank you. Yes, I will post to the numpy mailing list in future. Regards Saptarshi
On Jun 9, 4:04 pm, Robert Kern <[EMAIL PROTECTED]> wrote: > sapsi wrote: > > Hello, > > I have a numpy array (2 rows 3 colums) > > > import numpy > > a=numpy.array( [ [1,2,3] , [3,3,1] ]) > > > I wish to add a row, this is how i do it > > > s=a.shape > > numpy.resize(a,s[0]+1,s[1]) > > a[s[0]]=new row vector. > > > Q: Is this a costly operation? > > It can be if you have large arrays. > > > What happens if i have to it several > > (and unknown) number of times? > > is there a simpler way to add a row? > > numpy.vstack([a, newrow]) > > Generally speaking, you shouldn't resize numpy arrays. If you need to > construct > an array by appending, build up a list instead and use vstack() (or hstack() > or > dstack() or column_stack() or concatenate() depending on the geometry). > > We also have a numpy mailing list, which you should direct future numpy > questions to: > > http://www.scipy.org/Mailing_Lists > > -- > Robert Kern > > "I have come to believe that the whole world is an enigma, a harmless enigma > that is made terrible by our own mad attempt to interpret it as though it > had > an underlying truth." > -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
