Question

I need some clarification on how module and class level imports are handled when coexisting in the same namespace. See the following examples:

Works:

import datetime
print datetime.datetime.utcnow()

Fails:

from datetime import datetime
print datetime.datetime.utcnow()

Error: AttributeError: type object ‘datetime.datetime’ has no
attribute ‘datetime’

Works:

from datetime import datetime # Is this ignored?
import datetime
print datetime.datetime.utcnow()

What exactly is happening in the 3rd example? Is the second module import replacing the class-specific first import? Does this mean that module and class level imports shouldn’t be mixed in the same namespace?

Answer 1

There is no priority is such. The outcome is determined by the order in which import statements are executed, as follows.

If you try to import several things called X into your namespace, each import would rebind X to whatever it’s importing.

Therefore at the end it will be last import that’ll be in effect as far as the name X in concerned.

This is precisely what happens in your third example:

from datetime import datetime # This isn't ignored, but the name is immediately rebound
                              # by the next line
import datetime               # Rebinds the name