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Lecture 4 Name and Main
Tirsvad edited this page 2026-11-06 06:14:05 +01:00
Lecture 4: name and main
English · Dansk · Bahasa Malaysia
What the lecture covers
__name__ is a built-in variable that holds the name of the current module. When a file is run directly Python sets it to "__main__"; when the file is imported it holds the module name. Checking if __name__ == "__main__": lets a file decide what runs only when it is the main program, for example app.run(). That gives a second way to start the Flask server, next to flask run, and it makes starting and stopping easy during development.
What we gained
- The rule that code runs correctly whether a file is run or imported.
- A
main()function inhello.pythat is only called under the__main__check, so importing it never starts a server. - A tested example (
describe_name) that explains the two cases in words.
In this repository
Code: src/flask_day_54/presentation/hello.py (main) and src/flask_day_54/domain/name_demo.py. Tests: tests/unit/test_name_demo.py and tests/e2e/test_hello_main.py.