Deep copy and shallow copy in Python

Copy.copy a shallow copy copies only the parent object and does not copy the inner child objects of the object.

Copy.deepcopy deep Copy Copy objects and their sub-objects

Example:

>>> Import Copy

>>> a=[1,2,3,4,[' A ', ' B ']

>>> B=a # Pass reference. Equivalent to now B and a point to the same piece of memory area

In that case, any modification of a B will be synchronized

>>> C=copy.copy (a) # shallow copy. The equivalent of C and a are now two separate memory areas

>>> D=copy.deepcopy (a) # deep copy. Equivalent to a completely separate memory area

>>> A.append (5) # This is on the outer object that the parent object processing affects the copy shallow copy

>>> a[4].append (' C ') # This is an internal sub-object that does not affect. That is, it is still pointing to a piece

>>> print ' A ', a

A [1, 2, 3, 4, [' A ', ' B ', ' C '], 5]

>>> print ' B ', b

b [1, 2, 3, 4, [' A ', ' B ', ' C '], 5]

>>> print ' C ', C

c [1, 2, 3, 4, [' A ', ' B ', ' C ']]

>>> print ' d ', D

d [1, 2, 3, 4, [' A ', ' B ']

>>>

If they are copied, they are independent of each other.

Like Copy.copy, it's actually a shallow copy, because it's a parent object. Therefore: The parent object is not affected. is a separate two-block area.

Conclusion: which copy of which is a separate memory area. is separate from the original memory. You can't change it, and it won't affect me.

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