Difference between shallow copy and deep copy

The difference between deep copy and shallow copy ：
1、 The shallow copy just copies the reference address of the object , Two objects point to the same memory address , So modify any of these values , Another value will change with it , This is a shallow copy （ example ：assign()）

2、 Deep copy is to copy objects and values , Two objects modify any of the values and the other does not change , This is the deep copy .

The simple understanding is ： That is the assumption. B Copy the A, When modifying A when , see B Will it change , If B And then it changed , It means it's a shallow copy , Short hand , If B It hasn't changed , That's deep copy . If the element in the copied object has only value , There is no reference , There is no difference between a deep copy and a shallow copy , Will copy a copy of the original object , Generate a new object , Changing the value in the new object will not affect the original object , The new object is completely separated from the original object .

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Code implementation

import copy
a = [1,2,3,4,5,['a','b','c']]
b = a
c = copy.copy(a)
d = copy.deepcopy(a)
a.append(5)
a[5].append('d')
print('b',b) # [1,2,3,4,5,['a','b','c','d'],5]
print('c',c) # [1,2,3,4,5,['a','b','c','d']]
print('d',d)# [1,2,3,4,5,['a','b','c']]