Python interview questions and answers

Subclass django.db.models.Model and declare fields such as CharField or ForeignKey.

A QuerySet is a lazy representation of a database query.

Call MyModel.objects.all() to get a QuerySet of every row.

ForeignKey stores a many-to-one relation: many child rows point at one parent.

Migrations are versioned Python files that describe schema changes.

pip is Python's standard package installer.

Run python -m pip install package-name so you invoke the pip that belongs to that interpreter.

requirements.txt lists packages and versions so a project can be reproduced.

python -m pip freeze prints installed distributions in requirements format.

A venv is an isolated directory with its own interpreter and site-packages.

Run python -m venv .venv (or another folder name) from the project root.

From PowerShell, run .venv\Scripts\Activate.ps1

Global installs mix unrelated projects and can break the system Python that OS tools rely on.

A decorator is a callable that takes a function and returns a new callable, usually wrapping extra behavior.

@my_dec above a function is the same as func = my_dec(func) after the def.

wraps copies the wrapped function's metadata such as __name__ and __doc__ onto the wrapper.

A generator is an iterator produced by a function that uses yield, or by a generator expression.

yield pauses the function and returns a value to the caller, preserving local state.

Use a for loop, which calls next() until StopIteration.