[Numpy-discussion] concatenating 1-D arrays to 2D
Brian Blais
bblais at bryant.edu
Thu Mar 22 20:13:22 EDT 2007
Hello,
I'd like to concatenate a couple of 1D arrays to make it a 2D array, with two columns
(one for each of the original 1D arrays). I thought this would work:
In [47]:a=arange(0,10,1)
In [48]:a
Out[48]:array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
In [49]:b=arange(-10,0,1)
In [51]:b
Out[51]:array([-10, -9, -8, -7, -6, -5, -4, -3, -2, -1])
In [54]:concatenate((a,b))
Out[54]:
array([ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -10, -9, -8,
-7, -6, -5, -4, -3, -2, -1])
In [55]:concatenate((a,b),axis=1)
Out[55]:
array([ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -10, -9, -8,
-7, -6, -5, -4, -3, -2, -1])
but it never expands the dimensions. Do I have to do this...
In [65]:concatenate((a.reshape(10,1),b.reshape(10,1)),axis=1)
Out[65]:
array([[ 0, -10],
[ 1, -9],
[ 2, -8],
[ 3, -7],
[ 4, -6],
[ 5, -5],
[ 6, -4],
[ 7, -3],
[ 8, -2],
[ 9, -1]])
?
I thought there would be an easier way. Did I overlook something?
thanks,
Brian Blais
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bblais at bryant.edu
http://web.bryant.edu/~bblais
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