Python Modules and Packages Questions and Answers

Question 1

A developer is creating a large application with a directory structure for utilities like `my_app/utils/string_helpers.py`.
To make `utils` a package and allow `string_helpers` to be imported from `my_app/main.py` using `from utils import string_helpers`, what crucial, often empty, file must exist inside the `my_app/utils/` directory?

Accepted Answer

__init__.py

Answer

__main__.py

Answer

package.cfg

Answer

setup.py

Question 2

What is the primary purpose of the `if __name__ == '__main__':` construct in a Python script?

Accepted Answer

To allow code to run only when the script is executed directly, but not when it is imported as a module.

Answer

To define the main function that must be executed first in any script.

Answer

To mark the script as a private module that cannot be imported.

Answer

To automatically import all necessary dependencies for the script.

Question 3

A data scientist is working on a script and needs to use both the `numpy` and `pandas` libraries, which are conventionally imported with short aliases. Which of the following code snippets correctly imports these modules using their standard aliases?

Accepted Answer

import numpy as np
import pandas as pd

Answer

from numpy import np
from pandas import pd

Answer

import numpy, pandas as np, pd

Answer

alias numpy as np
alias pandas as pd

Question 4

When you execute `from math import sqrt`, what exactly happens in the current script's namespace?

Accepted Answer

The entire `math` module is loaded into memory, and a reference to the `sqrt` function is added directly to the current namespace.

Answer

The entire `math` module is loaded, and a reference to it is placed in the current namespace.

Answer

Only the `sqrt` function's code is loaded into memory, and the name `sqrt` is added to the current namespace.

Answer

A new module object named `sqrt` is created in the current namespace.

Question 5

Which of the following is the LAST place the Python interpreter will look when trying to resolve an `import my_module` statement?

Accepted Answer

Installation-dependent default directories, such as `site-packages`.

Answer

The directory containing the script that is running.

Answer

Directories listed in the `PYTHONPATH` environment variable.

Answer

A randomly selected user-created directory.

Question 6

A developer is building a package and wants to control which functions are imported when a user performs a wildcard import (`from my_package import *`). Which special variable should be defined within the package's `__init__.py` file to achieve this?

Accepted Answer

__all__

Answer

__exports__

Answer

__public__

Answer

__imports__