i have numpy array (of length x) of arrays, of of same length (y), has type "object" , has dimension (x,). "convert" array of dimension (x, y) type of elements of member arrays ("float"). the way can see "manually" like [x x in my_array] is there better idiom accomplishing "conversion"? for example have like: array([array([ 0., 0., 1., 0., 0., 0., 0., 0., 0., 0.]), array([ 0., 1., 0., 0., 0., 0., 0., 0., 0., 0.]), array([ 0., 0., 1., 0., 0., 0., 0., 0., 0., 0.]), ..., array([ 0., 0., 0., 0., 0., 0., 0., 0., 0., 1.]), array([ 0., 0., 0., 0., 0., 0., 0., 1., 0., 0.]), array([ 0., 0., 0., 0., 0., 0., 0., 0., 0., 1.])], dtype=object) which has shape (x,) rather (x, 10). you can concatenate arrays on new axis. example: in [1]: a=np.array([1,2,3],dtype=object) ...: b=np.array([4,5,6],dtype=object) to make array of array...