淺談Python的複製

morristai01@gmail.com (Morris) — Sun, 27 Aug 2017 11:46:56 +0800

這裡用三個不同list來示範不同copy的差別:

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import copy
a = [1, 2, 3]
b = [4, 5, 6]
c = [a, b]

Using normal assignment operatings to copy:

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d = c
print (id(c) == id(d)) # True - d和c是相同object
print (id(c[0]) == id(d[0])) # True - d[0]和c[0]是相同object

Using a shallow copy:

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d = copy.copy(c)
print (id(c) == id(d)) # False - d是新的object，跟c不同
print (id(c[0]) == id(d[0])) # True - d[0]和c[0]是相同object

Using a deep copy:

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d = copy.deepcopy(c)
print (id(c) == id(d)) # False - d是新的object，跟c不同
print (id(c[0]) == id(d[0])) # False - d[0]是新的object，跟c[0]不同

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