Django url pattern with or without <projectName> as path to view?

I'm new to Django and been reading the http://djangobook.com and finds that the following two patterns work the same way with no hiccups for project named mysite and views.py on the project root with a function named hello.

(r'^hello/$', 'mysite.views.hello')
开发者_JS百科(r'^hello/$', 'views.hello)

May I know what's the practice like? with or without the proceeding Project namespace? And if I may, why?

'' is the prefix for these patterns.

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the fisrt one is because the mysite dir is in your python path;

the second one is because when your run the project, the current path will add to python path.