Kind of new to python and I need to use numpy to append a column, I have an ndarray a with [[1 2 3] [4 5 6]]
and another ndarray with b [1 7]
so the end result should be [[1 2 3 1] [4 5 6 7]
. I have tried
array = np.append(a , b, axis=1)
but I get
all the input arrays must have same number of dimensions
(makes sense). I was also trying to insert it in a for loop but based on what i have seen with python these libraries have an easy way to do things and I was wondering if there is a more efficient way?
Try numpy.hstack
with added axis to b -
a = np.array([[1,2,3],[4,5,6]])
b = np.array([1,7])
np.hstack([a,b[:,None]])
array([[1, 2, 3, 1],
[4, 5, 6, 7]])
Notes:
b[:,None]
adds an axis to turn b from 1D (2,)
to 2D (2,1)
array (its the same as b.reshape(-1,1)
) np.hstack
is now able to horizontally stack (2,3)
and (2,1)
to give (2,4)
shaped array
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