Creating a Python Package

How to Package?

1 - Install Hatch (Already done)

pip install hatch

2 - Edit hatch config (optional)

code $(hatch config find)

• under [template.licenses]
  • set headers=false
  • set default=[]
• under [template.plugins.default] set
  • src-layout = true

3 - Use hatch to create project

hatch new traffic_light_counter

This creates a new folder called traffic_light_counter, but we actually want to copy the contents out of the folder. You can do it manually, or paste the below into the terminal;

rm traffic-light-counter/README.md; mv traffic-light-counter/* .; rmdir traffic-light-counter/

4 - Open pyproject.toml

• Add pandas dependency​ dependencies = ["pandas"]

5 - Run Hatch Shell

hatch shell

6 - Test everythign is working

hatch run cov

7 - Create .gitignore file

With the following contents

.pytest_cache
__pycache__
dist

8 - Copy paste code

Copy copy the code below into /src/traffic_light_counter/count_red_amber_green.py

def count_red_amber_green(column):
    column = column.str.lower().str.strip()
    return {
        "red"   : (
            column.str.endswith("red"  )
            | column.str.startswith("red"  )
        ).sum(),
        "amber" : (
            column.str.endswith("amber")
            | column.str.startswith("amber")
        ).sum(),
        "green" : (
            column.str.endswith("green")
            | column.str.startswith("green")
        ).sum(),
    }

9 - Modify __init__.py

Copy copy the code below into /src/traffic_light_counter/__init__.py

from .count_red_amber_green import count_red_amber_green

10 - Copy Paste Tests

Copy the code below to a new file in the tests folder:

tests/test_count_red_amber_green.py

def test_count_red_amber_green():
    import pandas as pd
    from traffic_light_counter import count_red_amber_green
    input = pd.Series([
        "Amber",
        "---red",
        "red--",
        "green",
        "green ",
    ])
    expected_result = {"red": 2, "amber": 1, "green": 2}
    actual_result = count_red_amber_green(input)
    assert actual_result==expected_result

11 - Run Tests

Get hatch to run tests, including code coverage report;

hatch run cov

NOTE: having problems here to fix try check pyproject.toml is correct:

[tool.hatch.version]
path = "src/traffic_light_counter/__about__.py"

then run

exit
hatch env purge
hatch shell

12 - Build wheel :)

hatch build

13 - exit hatch

exit
pip install dist/traffic_light_counter-0.0.1-py3-none-any.whl

Teacher's notes

Ignore this section of the readme

Cleanup workspace

rm -r src; rm -r tests; rm pyproject.toml; rm .gitignore; rm -r -f .pytest_cache; rm -r -f dist;rm .coverage