Python中深浅拷贝的区别详细分析

import copy
 
tup1 = (991, "abc")
tup2 = copy.copy(tup1) # 浅拷贝
# tup2 = tup1 # 在这个例子里浅拷贝等价于赋值
 
print(id(tup1))
print(id(tup2))
 
print(tup1 == tup2)
print(tup1 is tup2)
 
# 2457279675264
# 2457279675264
# True
# True
 
tup2 = copy.deepcopy(tup1) # 深拷贝
 
print(id(tup1))
print(id(tup2))
 
print(tup1 == tup2)
print(tup1 is tup2)
 
# 1291830377344
# 1291830377344
# True
# True

import copy
 
lis1 = [991, "abc", (9, 993), [994, 995], [888,887], {"name": "Tom"}, (996, [997, 998]), (888,(886, 886))]
lis2 = copy.copy(lis1) # 浅拷贝
 
print(id(lis1))
print(id(lis2))
 
print(lis1 == lis2)
print(lis1 is lis2)
 
# 2491304912896
# 2491304912960
# True
# False
 
lis2 = copy.deepcopy(lis1) # 深拷贝
print(id(lis1))
print(id(lis2))
 
print(lis1 == lis2)
print(lis1 is lis2)
 
# 2841088174144
# 2841088174208
# True
# False

import copy
tup3 = (991, "abc", [])
tup4 = copy.copy(tup3) # 浅拷贝
print(tup3 is tup4) # True
print(tup3[-1] is tup4[-1]) # True
lis1 = [991, "abc", (9, 993), [994, 995], [888,887], {"name": "Tom"}, (996, [997, 998]), (888,(886, 886))]
lis2 = copy.copy(lis1) # 浅拷贝
print(lis1 is lis2) # False
# 虽然 lis1 和 lis2 的地址不同，但其中的每个元素都各自指向同一个对象
print(lis1[0] is lis2[0]) # True
print(lis1[1] is lis2[1]) # True
print(lis1[2] is lis2[2]) # True
print(lis1[3] is lis2[3]) # True
print(lis1[4] is lis2[4]) # True
print(lis1[5] is lis2[5]) # True
print(lis1[6] is lis2[6]) # True
print(lis1[7] is lis2[7]) # True

import copy
lis1 = [991, "abc", (9, 993), [994, 995], [888,887], {"name": "Tom"}, (996, [997, 998]), (888,(886, 886))]
lis2 = copy.deepcopy(lis1) # 深拷贝
print(lis1 is lis2) # False，列表是可变对象，深复制后地址改变
print(lis1[0] is lis2[0]) # True，索引0是整数，不可变，地址不变
print(lis1[3] is lis2[3]) # False, 索引3是列表，可变，地址改变
tup3 = (991, "abc", [])
tup4 = copy.deepcopy(tup3) # 深拷贝
print(tup3 is tup4) # False，虽然 tup3 是不可变对象，但其内部存在可变对象，所以深复制后地址仍然改变
print(tup3[0] is tup4[0]) # True，索引 0 是整数，不可变，地址不变
print(tup3[1] is tup4[1]) # True，索引 3 是字符串，不可变，地址不变
print(tup3[2] is tup4[2]) # False，索引 3 是列表，可变，地址改变