Question

I have a class with __str__ and __repr__ defined:

class MyClass:
    def __init__(self, version):
        self.version = version
    def __repr__(self):
        return self.version

myObjs = {}
o = MyClass("1")
myObjs[o] = o
print myObjs

Which prints:

{1: 1}

How do I store the MyClass object as value to the dictionary instead of the string representation?
I could have added getVersion(), but just wanted to know if there is some more elegant way.

Thanks

Answer 1

As mentioned in the comments, the dictionary is storing the object.

class MyClass(object):
    def __init__(self, version):
        self.version = version
    def __repr__(self):
        return self.version

myObjs = {}
o = MyClass("1")
myObjs[o] = o
print type(o)                                                                   
print o.__class__                                                               
print myObjs                                                                    
print type(myObjs[o])

Prints the following:

<class '__main__.MyClass'>
<class '__main__.MyClass'>
{1: 1}
<class '__main__.MyClass'>

The reason it prints this way is because the dictionary uses the __repr__ of its keys and values for both its __str__ and __repr__ functions. You can always change your __repr__ function though to make it less ambiguous with an integer:

def __repr__(self):
    return '{0}({1})'.format(str(self.__class__.__name__), self.version)

Sample Output:

{MyClass(1): MyClass(1)}

Feel free to use whichever format that works best for you. I also changed your class to extend from object to make it a new style class (it brings classes and types together in the language and adds additional abilities to classes (such as decorators and the super function)). Otherwise:

print type(o)

Outputs

<type 'instance'>