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浅述python中深浅拷贝原理

yipeiwu_com5年前 (2020-03-06)Python基础

前言

在c++中参数传递有两种形式：值传递和引用传递。这两种方式的区别我不在此说，自行补上，如果你不知道的话。我先上python代码，看完我们总结一下，代码如下：

# copy module import
import copy

# number and string
a = 12
a1 = a
a2 = copy.copy(a)
a3 = copy.deepcopy(a)
# look addr
print("==========number=======")
print(id(a))
print(id(a1))
print(id(a2))
print(id(a3))

s = '12345'
s1 = s
s2 = copy.copy(s)
s3 = copy.deepcopy(s)
# look addr
print("==========String=======")
print(id(s))
print(id(s1))
print(id(s2))
print(id(s3))

# others
target = {
  'name': 'ckmike',
  'age': 25,
  'boxes':[
    'LV',
    'Prada',
    'KUQI'
  ]
}
target1 = target
target2 = copy.copy(target)
target3 = copy.deepcopy(target)
print("==========dict-1=======")
print(id(target))
print(id(target1))
print(id(target2))
print(id(target3))
print("==========dict-2=======")
print(id(target['boxes']))
print(id(target1['boxes']))
print(id(target2['boxes']))
print(id(target3['boxes']))

输出结果：

==========number=======
10943360
10943360
10943360
10943360
==========String=======
140567123944648
140567123944648
140567123944648
140567123944648
==========dict-1=======
140567124625088
140567124625088
140567124625160
140567123938760
==========dict-2=======
140567099339272
140567099339272
140567099339272
140567099339464