如何在python中克隆一个类的对象？

Question

I am creating a game that has a 'Battlefield.' I created a class for it:

class Battlefield:
    units = [[Warrior1, Warrior2]]

I am creating a function that would clone the units on the battlefield, so the new Battlefield.units would be:

print (Battlefield.units)
[[Warrior1, Warrior2], [Warrior1, Warrior2]]

'Warrior1'is something like

Warrior1 = [1, 3, 2, 5, 6]

What makes this difficult, is I need to be able to adjust the stats for ONLY the first Warrior1, without adjust the stats of the second Warrior1. All of the questions that I've seen on stack overflow have addressed how to copy a list onto a new list, such as:

new_list = old_list.copy()

However, I will not be able to reference this new_list in existing functions, since within the game I constantly refer back to the 'Battlefield.unit' object. In other words, I must clone WITHIN the existing object, all while making the variables within the list somehow distinct from one another so I can alter one without altering the other.

Please advise. Thank you!

Answer 1

You can use copy.deepcopy :

>>> import copy
>>> a = [[1, 2], [3,4]]
>>> b = copy.deepcopy(a)
>>> b[0][0] = 4
>>> a
[[1, 2], [3, 4]]
>>> b
[[4, 2], [3, 4]]

Or for an object oriented approach:

class Warrior():
  def __init__(self):
    pass
  def copy(self):
    return copy.deepcopy(self)