python when to use np arange code example

Example 1: np.arange in python

>>> np.arange(3)
array([0, 1, 2])
>>> np.arange(3.0)
array([ 0.,  1.,  2.])
>>> np.arange(3,7)
array([3, 4, 5, 6])
>>> np.arange(3,7,2)
array([3, 5])

Example 2: np arange shape

np.arange(12).reshape(3,4)