1. 浅拷贝
浅拷贝是对于一个对象的顶层拷贝
通俗的理解是：拷贝了引用，并没有拷贝内容
2. 深拷贝
深拷贝是对于一个对象所有层次的拷贝(递归)
进一步理解拷贝
In [
23]: a = [
11,
22,
33]
In [
24]: b = [
44,
55,
66]
In [
25]: c = (a,b)
In [
26]: e = copy.deepcopy(c)
In [
27]: a.append(
77)
In [
28]: a
Out[
28]: [
11,
22,
33,
77]
In [
29]: b
Out[
29]: [
44,
55,
66]
In [
30]: c
Out[
30]: ([
11,
22,
33,
77], [
44,
55,
66])
In [
31]: e
Out[
31]: ([
11,
22,
33], [
44,
55,
66])
In [
32]:
In [
32]:
In [
32]: f = copy.copy(c)
In [
33]: a.append(
88)
In [
34]: a
Out[
34]: [
11,
22,
33,
77,
88]
In [
35]: b
Out[
35]: [
44,
55,
66]
In [
36]: c
Out[
36]: ([
11,
22,
33,
77,
88], [
44,
55,
66])
In [
37]: e
Out[
37]: ([
11,
22,
33], [
44,
55,
66])
In [
38]: f
Out[
38]: ([
11,
22,
33,
77,
88], [
44,
55,
66])
3. 拷贝的其他方式
浅拷贝对不可变类型和可变类型的copy不同
In [
88]: a = [
11,
22,
33]
In [
89]: b = copy.copy(a)
In [
90]: id(a)
Out[
90]:
59275144
In [
91]: id(b)
Out[
91]:
59525600
In [
92]: a.append(
44)
In [
93]: a
Out[
93]: [
11,
22,
33,
44]
In [
94]: b
Out[
94]: [
11,
22,
33]
In [
95]:
In [
95]:
In [
95]: a = (
11,
22,
33)
In [
96]: b = copy.copy(a)
In [
97]: id(a)
Out[
97]:
58890680
In [
98]: id(b)
Out[
98]:
58890680
分片表达式可以赋值一个序列
a =
"abc"
b = a[:]
字典的copy方法可以拷贝一个字典
d = dict(name=
"zhangsan", age=
27)
co = d.copy()
有些内置函数可以生成拷贝(list)
a = list(range(
10))
b = list(a)
copy模块中的copy函数
import copy
a = (
1,
2,
3)
b = copy.copy(a)
面试可能会被面试官问到有关浅拷贝和深拷贝的问题
浅拷贝：如a = b，这种就是浅拷贝
深拷贝：copy.deepcopy（）是深拷贝
另外。copy.copy（）根据拷贝对象是可变类型和不可变类型时，处理方式也不同，简单说copy会对原对象拷贝，但不会递归深拷贝
