Python - lesson 3 | HackIndia Skills

Python - lesson 3 | HackIndia Skills | HackIndia

Example

Small module

Create a file named processor.py. This file holds logic you can import without running the whole tool.

# processor.py

def clean_text(text):
    return text.strip().lower()


def make_label(record):
    name = clean_text(record["name"])
    city = clean_text(record["city"])
    return f"{name} from {city}"


def build_output(records):
    labels = []
    for record in records:
        labels.append(make_label(record))
    return labels

Example

Runnable script

Create a second file named run_tool.py. This is the file someone will run from the terminal.

The if block means the tool runs only when this file is executed directly. It will not run by accident when another file imports it.

# run_tool.py

from processor import build_output


def main():
    sample_records = [
        {"name": " Asha ", "city": " Pune "},
        {"name": " Ravi ", "city": " Kochi "},
    ]

    labels = build_output(sample_records)

    for label in labels:
        print(label)


if __name__ == "__main__":
    main()

Tip

Ask AI well

AI tools are useful for refactoring a long script into functions. Paste only the relevant code and ask for small functions with clear names.

Check that the AI did not change your data shape, hide errors, or move file reading into every function. Run the script after every change.

Refactor this Python script into small functions.
Keep the same input and output.
Put reusable logic in processor.py.
Put the runnable main() in run_tool.py.
Do not add new libraries.

Common mistake

Do not call main() at the bottom of a module file that you plan to import. That can make code run twice or run at the wrong time.

Use the __name__ check in the script that is meant to be executed.

# Good
if __name__ == "__main__":
    main()

Write functions and modules

One idea

Why this matters

Split the job