用於App Engine的Python中的克隆和Expando類對象

Question

在Google App Engine上使用Python時克隆（複製）Expando類對象的好方法是什麼？

我碰到一些代碼來了這裏，但除非我錯了，它不expando屬性工作：Copy an entity in Google App Engine datastore in Python without knowing property names at 'compile' time

謝謝！

Answer 1

這裏是Nick's function的修訂版，其中包括動態屬性：

def clone_entity(e, **extra_args): 
    """Clones an entity, adding or overriding constructor attributes. 

    The cloned entity will have exactly the same property values as the original 
    entity, except where overridden. By default it will have no parent entity or 
    key name, unless supplied. 

    Args: 
    e: The entity to clone 
    extra_args: Keyword arguments to override from the cloned entity and pass 
     to the constructor. 
    Returns: 
    A cloned, possibly modified, copy of entity e. 
    """ 
    klass = e.__class__ 
    props = dict((k, v.__get__(e, klass)) for k, v in klass.properties().iteritems()) 
    props.update(dict([(k, getattr(e, k)) for k in e.dynamic_properties()])) 
    props.update(extra_args) 
    return klass(**props)