Entry

How do I copy one object into another without having them refer to each other?

May 12th, 2000 07:29
unknown unknown, Emile van Sebille, Thomas Thiele

You could create a separate instance, or provide a copy
function as part of the class.

>>> a = A('bragi')
>>> b = A('')
>>> b.name = a.name
>>> b.name
'bragi'
>>> a.name = 'stini'
>>> b.name
'bragi'
>>> 


>>> class A:
        def __init__(self,name):
                self.name = name
        def copy(self):
                retval = A(self.name)
                # other copy functions
                return retval

        
>>> a = A('bragi')
>>> b = a.copy()
>>> b.name
'bragi'
>>> a.name = 'stini'
>>> b.name
'bragi'
>>> 

Or, you could use copy.copy and copy.deepcopy.

>>> class X:
...     def __init__(self):
...             self.a = 5
...
>>> x = X()
>>> list = [x]
>>> cl1 = copy.copy(list)
>>> cl2 = copy.deepcopy(list)
>>> list[0].a = 6
>>> list[0].a
6
>>> cl1[0].a
6
>>> cl2[0].a
5