App engine - check to see if a property exists within Expando class

问题

What is a good way to check to see if a property is populated in an expando class (Python for App Engine)

Can I do:

if Expando_class_name.property_name_to_check:
    do = someStuff

Or is that going to give me an error?

Thanks!

回答1:

Use hasattr:

if hasattr(expando_instance, 'foo'):
  # Do something with expando_instance.foo

回答2:

A better way is to use the dynamic_properties method.

if 'foo' in entity.dynamic_properties():  pass

来源：https://stackoverflow.com/questions/6339032/app-engine-check-to-see-if-a-property-exists-within-expando-class