py_list_shallow_deep_cp.py

# Python List makes a shallow copy by default and doesn't copy-on-write.

list_a = [1,2,3]
list_shallow = list_a
list_shallow.append(4)
print(list_a) # [1, 2, 3, 4]
list_a.append(5)
print(list_shallow) # [1, 2, 3, 4, 5]

list_a = [1,2,3]
list_deep = list_a[:]
list_deep.append(4)
print(list_a) # [1, 2, 3]
list_a.append(5)
print(list_deep) # [1, 2, 3, 4]