导入和使用datetime python库的正确方法

Question

Why can't I just do datetime.now()? Python doesn't like this?? Whats the correct why to import and use the datetime library in python...?

import datetime
now = datetime.datetime.now()
print "Time: %d:%02d - Date: %d/%d/%d <br>" %(now.hour, now.minute, now.month, now.day, now.year)

Answer 1

That's because you are importing the datetime module (which contains classes for manipulating dates and times as stated in the documentation ) not the datetime object. In such classes and objects inside the datetime module exists an object named datetime (yes, the same name as the module where it lives), so to use the datetime object the way you want you need to import it like this:

from datetime import datetime
#       ^               ^
#       |               |
#    module      class inside module

# Now you can use
now = datetime.now()

Answer 2

The datetime module contains a number of classes , including the class datetime.datetime . If you don't care about the other functions in the module, you can write:

from datetime import datetime as datetime_class
datetime_class.now()

However, I strongly suggest simply writing datetime.datetime.now() .