ndarray.ndim Number of array dimensions. c=np.array([ [[1,2,3],[3,4,4]], [[5,6,6],[7,8,8]] ]) print(c.ndim) print(c.shape) >>> 3 (2, 2, 3) ravel It returned 1-d array. np.array([[1,2,3],[4,5,6]]).ravel() >>> array([1, 2, 3, 4, 5, 6]) Same as below. np.array([[1,2,3],[4,5,6]]).reshape(-1) >>> array([1, 2, 3, 4, 5, 6]) permutation It returns the permutated range. np.random.permutation(10) >>> arra..