Deep copy and shallow copy in Python

bytes

Python Bytes/str
Bytes in the Python3 as a separate data type, can not be spliced, not splicing, not splicing

>>> '€20'.encode('utf-8')b'\xe2\x82\xac20'>>> b'\xe2\x82\xac20'.decode('utf-8')'€20'

Decoding

>>> b'\xa420'.decode('windows-1255')'?20'

Deep copy and shallow copy
Deep copy creates a new object to reassign the memory address and copy the object contents. Shallow copy does not reassign the memory address, which points to the previous memory address. Shallow copy if the object has references to other objects, the contents of the child object are changed if the child object is modified.

import copy#这里有子对象numbers=['1','2','3',['4','5']]#浅copynum1=copy.copy(numbers)#深copynum2=copy.deepcopy(numbers)#直接对对象内容进行修改num1.append('6')#这里可以看到内容地址发生了偏移，增加了偏移‘6’的地址print('numbers:',numbers)print('numbers memory address:',id(numbers))print('numbers[3] memory address',id(numbers[3]))print('num1:',num1)print('num1 memory address:',id(num1))print('num1[3] memory address',id(num1[3]))num1[3].append('6')print('numbers:',numbers)print('num1:',num1)print('num2',num2)输出：numbers: ['1', '2', '3', ['4', '5']]numbers memory address: 1556526434888numbers memory address 1556526434952num1: ['1', '2', '3', ['4', '5'], '6']num1 memory address: 1556526454728num1[3] memory address 1556526434952numbers: ['1', '2', '3', ['4', '5', '6']]num1: ['1', '2', '3', ['4', '5', '6'], '6']num2 ['1', '2', '3', ['4', '5']]

Deep copy and shallow copy in Python