Indexing can be done in numpy by using an array as an index. In case of slice, a view or shallow copy of the array is returned but in index array a copy of the original array is returned. Numpy arrays can be indexed with other arrays or any other sequence with the exception of tuples.
# Python program to demonstrate # the use of index arrays. import numpy as np # Create a sequence of integers from 10 to 1 with a step of -2 a = np.arrange(10, 1, -2) print("\n A sequential array with a negative step: \n",a) # Indexes are specified inside the np.array method. newarr = a[np.array([3, 1, 2 ])] print("\n Elements at these indices are:\n",newarr)
A sequential array with a negative step: [10 8 6 4 2] Elements at these indices are: [4 8 6]
We can slice a NumPy array in a similar way to slicing a list - except you can do it in more than one dimension.