Module copy
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Module copy

source code

Generic (shallow and deep) copying operations.

Interface summary:

        import copy

        x = copy.copy(y)        # make a shallow copy of y
        x = copy.deepcopy(y)    # make a deep copy of y

For module specific errors, copy.Error is raised.

The difference between shallow and deep copying is only relevant for
compound objects (objects that contain other objects, like lists or
class instances).

- A shallow copy constructs a new compound object and then (to the
  extent possible) inserts *the same objects* into it that the
  original contains.

- A deep copy constructs a new compound object and then, recursively,
  inserts *copies* into it of the objects found in the original.

Two problems often exist with deep copy operations that don't exist
with shallow copy operations:

 a) recursive objects (compound objects that, directly or indirectly,
    contain a reference to themselves) may cause a recursive loop

 b) because deep copy copies *everything* it may copy too much, e.g.
    administrative data structures that should be shared even between
    copies

Python's deep copy operation avoids these problems by:

 a) keeping a table of objects already copied during the current
    copying pass

 b) letting user-defined classes override the copying operation or the
    set of components copied

This version does not copy types like module, class, function, method,
nor stack trace, stack frame, nor file, socket, window, nor array, nor
any similar types.

Classes can use the same interfaces to control copying that they use
to control pickling: they can define methods called __getinitargs__(),
__getstate__() and __setstate__().  See the documentation for module
"pickle" for information on these methods.



Classes [hide private]
  Error
  _EmptyClass
  error
Functions [hide private]
 
_copy_immutable(x) source code
 
_copy_inst(x) source code
 
_copy_with_constructor(x) source code
 
_copy_with_copy_method(x) source code
 
_deepcopy_atomic(x, memo) source code
 
_deepcopy_dict(x, memo) source code
 
_deepcopy_inst(x, memo) source code
 
_deepcopy_list(x, memo) source code
 
_deepcopy_tuple(x, memo) source code
 
_getspecial(cls, name) source code
 
_keep_alive(x, memo)
Keeps a reference to the object x in the memo.
source code
 
_reconstruct(x, info, deep, memo=None) source code
 
_test() source code
 
copy(x)
Shallow copy operation on arbitrary Python objects.
source code
 
deepcopy(x, memo=None, _nil=[])
Deep copy operation on arbitrary Python objects.
source code
Variables [hide private]
  PyStringMap = None
  _copy_dispatch = {<type 'bool'>: <function _copy_immutable at ...
  _deepcopy_dispatch = {<type 'bool'>: <function _deepcopy_atomi...
  dispatch_table = {<type 'cStringIO.StringO'>: <function pickle...
  name = 'CodeType'
Function Details [hide private]

_keep_alive(x, memo)

source code 

Keeps a reference to the object x in the memo.

Because we remember objects by their id, we have to assure that possibly temporary objects are kept alive by referencing them. We store a reference at the id of the memo, which should normally not be used unless someone tries to deepcopy the memo itself...

copy(x)

source code 

Shallow copy operation on arbitrary Python objects.

See the module's __doc__ string for more info.

deepcopy(x, memo=None, _nil=[])

source code 

Deep copy operation on arbitrary Python objects.

See the module's __doc__ string for more info.

Variables Details [hide private]

_copy_dispatch

Value:
{<type 'bool'>: <function _copy_immutable at 0x771830>,
 <type 'instance'>: <function _copy_inst at 0x7718f0>,
 <type 'classobj'>: <function _copy_immutable at 0x771830>,
 <type 'complex'>: <function _copy_immutable at 0x771830>,
 <type 'float'>: <function _copy_immutable at 0x771830>,
 <type 'int'>: <function _copy_immutable at 0x771830>,
 <type 'list'>: <function _copy_with_constructor at 0x771870>,
 <type 'long'>: <function _copy_immutable at 0x771830>,
...

_deepcopy_dispatch

Value:
{<type 'bool'>: <function _deepcopy_atomic at 0x771970>,
 <type 'instance'>: <function _deepcopy_inst at 0x771ab0>,
 <type 'classobj'>: <function _deepcopy_atomic at 0x771970>,
 <type 'complex'>: <function _deepcopy_atomic at 0x771970>,
 <type 'float'>: <function _deepcopy_atomic at 0x771970>,
 <type 'int'>: <function _deepcopy_atomic at 0x771970>,
 <type 'list'>: <function _deepcopy_list at 0x7719b0>,
 <type 'long'>: <function _deepcopy_atomic at 0x771970>,
...

dispatch_table

Value:
{<type 'cStringIO.StringO'>: <function pickleStringO at 0x3152d30>,
 <type 'cStringIO.StringI'>: <function pickleStringI at 0x3152db0>,
 <type 'instancemethod'>: <function pickleMethod at 0x3152c30>,
 <type 'complex'>: <function pickle_complex at 0x42570>,
 <type 'module'>: <function pickleModule at 0x3152cb0>,
 <type '_sre.SRE_Pattern'>: <function _pickle at 0x7b070>,
 <type 'posix.stat_result'>: <function _pickle_stat_result at 0x427b0>\
,
...