Can someone please explain this weird Pygame importing convention?

Question

I see that people usually import Pygame like this:

import pygame
from pygame.locals import *

I don't understand what's the second line for. If we already imported the whole of Pygame, why import pygame.locals? Doesn't Pygame already include it once it's imported?

Answer 1

import pygame

imports the pygame module into the "pygame" namespace.

from pygame.locals import *

copys all names in pygame.locals into your current namespace. This is not neccessary, but saves you typing.

Answer 2

Actually, from the pygame docs:

This module contains various constants used by Pygame. It's contents are automatically placed in the pygame module namespace. However, an application can use pygame.locals to include only the Pygame constants with a 'from pygame.locals import *'.

So all these constants are already there when you use import pygame. We can see this if we do this:

>>> import pygame
>>> from pygame.locals import *
>>> set(dir(pygame.locals)).issubset(set(dir(pygame)))
True

So, pygame.locals is a subset of import pygame.. So absolutely no point doing it if you have already imported pygame! Apart from it allows you to access them without the pygame prefix.