Numpy: slice is a reference
The slice in numpy does not copy the data structure
examples/numpy/slice_1d.py
import numpy as np a = np.array([1, 1, 2, 3, 5, 8, 13, 21, 34]) print(a) # [ 1 1 2 3 5 8 13 21 34] b = a[2:5] print(b) # [2 3 5] a[2] = 20 print(a) # [ 1 1 20 3 5 8 13 21 34] print(b) # [20 3 5]