On Saturday, April 9, 2011 6:37:15 PM UTC-4, niknok wrote:
>
> Hello.
>
> What is the difference between the statements: import datetime vs from
> datetime import datetime
>
> I got stuck with my IS_DATE_IN_RANGE error "<type
> 'exceptions.AttributeError'>(type object 'datetime.datetime' has no
> attribute 'timedelta')" until i added "import datetime" to the controller.
> All the while, I thought I already loaded datetime because I already have
> this line: "from datetime import datetime".
>
The different methods of importing result in different namespaces -- see
http://effbot.org/zone/import-confusion.htm.
The datetime module is probably particularly confusing because the module
also includes a datetime class, so datetime.datetime refers to the datetime
class within the datetime module. If you do 'from datetime import datetime',
you're only importing the datetime class, so when you refer to 'datetime' in
your code, it's referring to the datetime class, not the whole datetime
module. That means 'datetime.timedelta' won't work, because it's expecting
'timedelta' to be an attribute of the datetime class, when it's actually a
class within the datetime module. If you want to use from-import to access
the timedelta class, you can do 'from datetime import timedelta', and then
you can refer to 'timedelta' directly.
Anthony
