copy module python documentation code example

Example 1: example of a deep copy in python

# deep copy example in python
import copy

old_list = [[1, 1, 1], [2, 2, 2], [3, 3, 3]]
new_list = copy.deepcopy(old_list)

old_list[1][0] = 'BB'

print("Old list:", old_list)
print("New list:", new_list)

# OUTPUT
Old list: [[1, 1, 1], ['BB', 2, 2], [3, 3, 3]]
New list: [[1, 1, 1], [2, 2, 2], [3, 3, 3]]

Example 2: python copy instance

import copy

class A(object):
  def __init__(self, a)
  	self.a = a

a = A(38)

# Deepcopy
a2 = copy.deepcopy(a)

# Shallow copy -> use this if copy.deepcopy() fails
a3 = copy.copy(a)