Deep copy and shallow copy of Python list-and method of initializing blank list (2)

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In fact, Python is still very flexible with deep copy and shallow copy processing, and even has a special toolkit copy to do something

Consider the following copy of this list:

Known Lista is a list that has already been defined.

Listb=lista

Note that this is not a copy of the process, here Lista and listb exactly the same

Here are some copy methods, but note whether it is a deep copy or a shallow copy:

Definition: lista=[2,[4,5]]

listb=lista[:]

Listb=list (Lista)

Listb=[i for i in Lista]

Import copy;listb=copy.copy (lista)

Import copy;listb=copy.deepcopy (lista)

Once the copy is complete, do the following:

Listb[1].append (9)

Print Lista,listb

The results of the five copy methods are as follows:

[2,[4,5,9]],[2,[4,5,9]]

[2,[4,5,9]],[2,[4,5,9]]

[2,[4,5,9]],[2,[4,5,9]]

[2,[4,5,9]],[2,[4,5,9]]

[2,[4,5]],[2,[4,5,9]]

Reference: http://blog.csdn.net/a6225301/article/details/48833125

Deep copy and shallow copy of Python list-and method of initializing blank list (2)