I have a matrix m = np.matrix([[1, 2, 3], [4, 5, 6]]).
I extract a vector v = m[0] + m[1], so that now v == [[5, 7, 9]]. The vector's shape is (1, 3), meaning it's considered a matrix, not a vector. How can I make v an actual vector, i.e something of shape (3,)?
I tried to use np.asarray(v) and np.array(v) but they don't do what I want.
Use np.squeeze(np.asarray(v)). So you first convert to an array (which other than matrices can have arbitrary n dimensions), then get rid of the extra dimension.
...or avoid using np.matrix in the first place, sparing you the extra step.
I guess the shortest would be
m.A.sum(0)
# array([5, 7, 9])
This converts to array before summing.
If you are starting from an 1xN matrix like v:
v.A1
# array([5, 7, 9])
