Why write datetime twice?

Hi there!

It's because you're importing the datetime module, a file like file.py, and inside that module you're selecting the class called datetime, from there you're selecting the now() method. So it goes:

• datetime - tells python to select in the datetime module
• datetime - tells python to select the class datatime in that module
• now - tells python to select the method now in that class
• () - execute that module.

For example, here's a file named... bob.py:

class Bob:
    _name = Bob

    @classmethod
    def bob(cls):
        cls()
        return cls._name

It's pretty basic I know, but if I wanted to use this in my python file i would do:

import bob

name = bob.Bob.bob()

You're right it looks a bit silly. That's why often people do things like:

from datetime import datetime as dt
time_now = dt.now()

or

import datetime as dt
time_now = dt.datetime.now

Basically all you have to remember is that in python the dot means we're going one level inside the object to the left of the dot. Again, for example:

print(object.__class__.__name__)

Here from left to right we select the main object class (where all classes come from), then inside that class there's a __class __ method which is actually a refrence to the type of the class, so we can step inside that again and get to __name __ which will return the name of the type.

Hope it helps :)

PS if you're interested you can see the actual datetimemodule file used by cpython here: https://github.com/python/cpython/blob/master/Modules/_datetimemodule.c It's written in C not python, but the principle is the same :)