Module 6
Modular Programming
6.2 Packages
Packages are a way of hierarchically structuring Python’s module namespace. For example, the module name name1.name2 designates a submodule named name2 in a package named name1.
In the same way that modules help avoid collisions between global variable names, packages help avoid collisions between module names.
Creating Packages
A Python package is simply a directory consisting of one or more Python modules (scripts).
Image Source: AITechTonic
Importing packages and its modules
import package_name[, package_name, ...]
import game
import package_name.module_name[, package_name.module_name, ... ]
import game.sound.load, game.image.open
from package_name.module_name import names
from game.level.start import level_one
Package Initialization
When a package or a module is imported, __init__.py is invoked, if present. __init__.py can be used for execution of package initialization code, such as initialization of package-level data.
print(f'Invoking __init__.py for {__name__}')
A = ['quux', 'corge', 'grault']
Now when the package is imported, global list A is initialized.
The statment import package_name only imports the package and doesn’t import any modules. We can import the modules by writing the following in __init__.py.
import package_name.module_name
Third-party Modules
PIP
PIP is a package manager for Python modules/packages. For Python 3.4 or later, PIP is included in default.
Check if PIP is installed
pip --version
Installing Pip
You can download and install pip. More details on Link
Downloading and installing a package
pip install package_name
pip install flask
Uninstalling a package
pip uninstall package_name
List packages
pip list