导入 copya = \'deepak\'b = 1, 2, 3, 4c = [1, 2, 3, 4]d = {1: 10, 2: 20, 3: 30}a1 = copy.copy(a)b1 = copy.copy(b)c1 = copy.copy(c)d1 = copy.copy(d) print(\'immutable - id(a)==id(a1)\', id(a...
import copy
a = "deepak"
b = 1, 2, 3, 4
c = [1, 2, 3, 4]
d = {1: 10, 2: 20, 3: 30}
a1 = copy.copy(a)
b1 = copy.copy(b)
c1 = copy.copy(c)
d1 = copy.copy(d)
print("immutable - id(a)==id(a1)", id(a) == id(a1))
print("immutable - id(b)==id(b1)", id(b) == id(b1))
print("mutable - id(c)==id(c1)", id(c) == id(c1))
print("mutable - id(d)==id(d1)", id(d) == id(d1))
我得到以下结果：
immutable - id(a)==id(a1) True
immutable - id(b)==id(b1) True
mutable - id(c)==id(c1) False
mutable - id(d)==id(d1) False
如果我执行深度复制：
a1 = copy.deepcopy(a)
b1 = copy.deepcopy(b)
c1 = copy.deepcopy(c)
d1 = copy.deepcopy(d)
结果是一样的：
immutable - id(a)==id(a1) True
immutable - id(b)==id(b1) True
mutable - id(c)==id(c1) False
mutable - id(d)==id(d1) False
如果我进行赋值操作：
a1 = a
b1 = b
c1 = c
d1 = d
结果是：
immutable - id(a)==id(a1) True
immutable - id(b)==id(b1) True
mutable - id(c)==id(c1) True
mutable - id(d)==id(d1) True
有人能解释一下这些副本之间到底有什么区别吗？这和可变和不可变对象有关吗？如果是的话，你能给我解释一下吗？
正常的赋值操作只会将新变量指向现有对象。 docs 解释了浅拷贝和深拷贝之间的区别：
浅复制和深复制之间的区别仅与复合对象（包含其他对象的对象，如列表或类实例）有关：
p2
p3
以下是一个小演示：
import copy
a = [1, 2, 3]
b = [4, 5, 6]
c = [a, b]
使用正常赋值操作来复制：
d = c
print id(c) == id(d) # True - d is the same object as c
print id(c[0]) == id(d[0]) # True - d[0] is the same object as c[0]
使用浅拷贝：
d = copy.copy(c)
print id(c) == id(d) # False - d is now a new object
print id(c[0]) == id(d[0]) # True - d[0] is the same object as c[0]
使用深层复制：
d = copy.deepcopy(c)
print id(c) == id(d) # False - d is now a new object
print id(c[0]) == id(d[0]) # False - d[0] is now a new object