# Python Programming

## One script
1. Create a python script file (`.py`)
2. Write statements and save
3. Run command: `python <path to file>`
4. Or start the file with `#! /usr/bin/python` then give execute permission `chmod +x <file>` and run the file only.

## Project

### Project structure
1. Create a working directory with structure
```
myproject/
│
├── src/
│   └── myprogram/
│       ├── __init__.py
│       ├── __main__.py
│       ├── config.toml
│       ├── module1.py
│       └── module2.py
│
├── tests/
│   ├── test_module1.py
│   └── test_module2.py
│
├── LICENSE
├── MANIFEST.in
├── README.md
└── pyproject.toml
```
2. The `__main__.py` will be the entry point of the program and has code pattern:
```python
from myprogram import module1, module2
def main():
	"""program function description"""

if __name__ == "__main__":
    main()
```
3. The `__init__.py` to represents the root of the package. It will have package constants, configuration handler. Variables defined in `__init__.py` become available as variables in the package namespace. Best practice for this file:
```python
from importlib import resources
try:
    import tomllib
except ModuleNotFoundError:
    import tomli as tomllib

__version__ = "1.0.0"

_cfg = tomllib.loads(resources.read_text("reader", "config.toml"))
URL = _cfg["feed"]["url"]
```
4. The `module1.py` and `module2.py` provides functions, object types that is used by `__main__.py`. Import the package itself can help the module access the package constants and variables. Example a module file:
```python
import myprogram

def function1():
	'''describe the feature of function1'''
	...
def function2():
	'''describe the feature of function2'''
	...
```
5. The `pyproject.toml` contains metadata of the package, it describes:
	1. Which build-system: a tool  responsible for creating the actual files that you’ll upload to PyPI.
	2. Dependencies
	3. Project information

### Using project localy


### Build package
1. Install two tools **build** and **twine**: `python -m pip install build twine`
3. Build the package: in the project root folder, run `python -m build`
4. Result: a dist folder created with two package formats created in .tar.gz and .whl in
5. Confirm the package build:
	- `unzip` the .tar.gz and inspect contents with `tree`.
	- or run `twine check dist/`
### Upload to the [[PyPI - Python Package Index]]
1. Create an account on https://pypi.org/
2. Run command `twine upload -r testpypi dist/*`
3. Twine will ask you for your username and password.
---
*Reference:* https://realpython.com/pypi-publish-python-package/