PCAP Modules and Packages Practice Test 5 — 15 Questions

Question 1

A package 'tools' has the structure: tools/__init__.py, tools/calc.py, tools/io.py. In __init__.py, the developer writes: from . import calc. A user tries: import tools; print(tools.add(1,2)). This fails with AttributeError. Why?

Accepted Answer

The add function is not imported into the tools package namespace.. Option A is correct because the `__init__.py` file only imports the `calc` module itself into the `tools` package namespace, not the `add` function. When a user calls `tools.add(1,2)`, Python looks for `add` directly in the `tools` namespace, but it is not there — it is only accessible as `tools.calc.add`. The `from . import calc` statement binds the name `calc` to the module, not its contents.

Answer

The function add is not defined in calc.py.

Answer

Relative imports are not allowed in __init__.py files.

Answer

The user should use tools.calc.add instead.

Question 2

A script runs: import sys; print(sys.path[0]). The output is an empty string. What does this indicate?

Accepted Answer

The script is being read from stdin.. When a script is read from stdin (e.g., via `python < script.py` or `echo 'print(1)' | python`), Python sets `sys.path[0]` to an empty string because there is no script file path to derive the directory from. This is the documented behavior: `sys.path[0]` is the directory containing the script, or an empty string if the script is read from standard input.

Answer

Python was launched with the -I flag.

Answer

The current working directory is not in sys.path.

Answer

The script is running from an interactive shell.

Question 3

A developer runs pip install requests. Later, they need to find out where the module is installed on the system. Which command shows the location?

Accepted Answer

python -c "import requests; print(requests.__file__)". Option C is correct because after importing a module in Python, its `__file__` attribute contains the absolute path to the module's `.py` file (or compiled `.pyc` file). The command `python -c "import requests; print(requests.__file__)"` first imports the module, then prints the location where Python found it, which is the exact installation path on the system.

Answer

python -c "print(requests.__path__)"

Answer

pip list --path

Answer

pip show requests

Question 4

Which TWO of the following are valid ways to import a function named 'func' from a module 'mymod' that is in the same directory as the script?

Accepted Answer

from mymod import func as myfunc. Option A is correct because the syntax `from mymod import func as myfunc` is a valid Python import statement that imports the function `func` from the module `mymod` and binds it to the local name `myfunc`. Since `mymod` is in the same directory as the script, Python's module search path includes that directory, so the import succeeds without needing a relative import prefix.

Answer

import mymod.func

Answer

import func from mymod

Answer

from .mymod import func

Question 5

Which THREE of the following are true about the __pycache__ directory?

Accepted Answer

It is automatically created when a module is imported.. Option B is correct because Python automatically creates the __pycache__ directory when a module is imported for the first time. This directory stores compiled bytecode files (.pyc) that allow Python to skip recompilation on subsequent imports, thereby improving startup time for later runs.

Answer

It is only created when the script is compiled with -O.

Answer

It should be added to version control.

Question 6

Which TWO of the following are true about importing modules using the import statement?

Accepted Answer

The module is executed only once on the first import.. Option A is correct because Python caches imported modules in the sys.modules dictionary. When a module is imported for the first time, it is executed and its code is stored; subsequent imports of the same module simply retrieve the cached object from sys.modules without re-executing the module's code. This ensures that module-level initialization runs only once, preventing side effects like repeated resource allocation or redefinition of global variables.

Answer

Relative imports can be used in scripts executed as the main module.

Answer

Importing a module with a different name using 'as' creates a copy of the module.

Answer

Circular imports always cause an ImportError.

Question 7

A user runs script.py and gets the above error. Which of the following is the most likely cause?

Accepted Answer

The package mypackage is not installed or not in the Python path.. The error message indicates that Python cannot find the module `mypackage`. This typically happens when the package is not installed (e.g., via pip) or the directory containing it is not in `sys.path`. Option C correctly identifies this as the most likely cause, as Python raises an `ImportError` when it cannot locate a module or package during import.

Answer

The function myfunction does not exist in mypackage.

Answer

The script.py is inside the mypackage directory, causing a conflict.

Answer

There is a syntax error in script.py.

Question 8

A developer runs pip install package==1.0 and gets the above error. What is the most likely solution?

Accepted Answer

Use pip install package==2.0 instead.. Option C is correct because the error indicates that version 1.0 of the package does not exist in the repository. By specifying a higher version like 2.0 that does exist, pip can successfully download and install the package. This is a common scenario when a package has never released version 1.0 or has skipped it.

Answer

Run pip update to upgrade pip.

Answer

Install from a different repository.

Answer

Check if the package name is correct.

Question 9

In module_b.py, the developer writes: from mypackage import module_a. When running a script that imports mypackage, an ImportError occurs. Which change should solve the issue?

Accepted Answer

Use from .. import module_a (relative import).. Option A is correct because the error occurs when module_b.py is inside the mypackage directory but uses an absolute import (from mypackage import module_a) that fails when mypackage is not on sys.path or is being executed as a script. Changing to a relative import (from .. import module_a) makes the import relative to the current module's location, allowing module_b to import module_a from its parent package without relying on the package being installed or on sys.path.

Answer

Add 'module_a' to __all__ in mypackage/__init__.py.

Answer

Move module_b.py to the mypackage directory.

Answer

Use import mypackage.module_a instead.

Question 10

A developer needs to add a custom directory '/home/user/mylibs' to Python's module search path so that modules in that directory can be imported. Which code snippet accomplishes this correctly?

Accepted Answer

import sys; sys.path.append('/home/user/mylibs'). Option A is correct because Python's module search path is stored in the list `sys.path`, and the standard way to add a custom directory at runtime is to use the `list.append()` method. This inserts the directory at the end of the search path, allowing modules in that directory to be imported after the standard library and site-packages directories.

Answer

import sys; sys.path.push('/home/user/mylibs')

Answer

import sys; sys.path.add('/home/user/mylibs')

Answer

import path; path.add('/home/user/mylibs')

Question 11

A package named 'utilities' contains a submodule 'strings'. Which import statement allows the use of the function 'reverse' defined in utilities.strings as reverse() without needing to prefix it?

Accepted Answer

from utilities.strings import reverse. Option D is correct because it directly imports the `reverse` function from the `utilities.strings` submodule into the current namespace, allowing it to be called as `reverse()` without any prefix. This is the only option that imports the specific function rather than the module or package.

Answer

import utilities.strings

Answer

from utilities import strings

Answer

from utilities import *

Question 12

A Python script is written to be used both as a standalone program and as an imported module. Which condition should the script use to execute code only when run directly?

Accepted Answer

if __name__ == '__main__':. Option B is correct because Python sets the global variable `__name__` to `'__main__'` when the script is executed directly (e.g., `python script.py`). When the script is imported as a module, `__name__` is set to the module's name. The condition `if __name__ == '__main__':` is the standard Python idiom to guard code that should only run in the direct execution context.

Answer

if __import__ == '__main__':

Answer

if __name__ == '__module__':

Answer

if __file__ == 'main':

Question 13

Two modules, 'module_a' and 'module_b', import each other. When 'module_a' is imported first, it tries to import 'module_b', which in turn tries to import 'module_a' again, causing a circular import error. Which of the following is the most effective strategy to resolve this circular dependency?

Accepted Answer

Move the shared code into a third module that both can import.. Option A is the most effective because it removes the circular dependency entirely. Option D (lazy import) can work but is often considered a workaround; restructuring is cleaner. Options B and C are not standard solutions.

Answer

Place all code in a single module.

Answer

Use relative imports instead of absolute imports.

Answer

Use the import statement inside function definitions to defer imports.

Question 14

A package 'shapes' has an __init__.py file. Which statement must be included in the __init__.py file to allow the syntax 'from shapes import *' to import all submodules 'circle', 'square', and 'triangle'?

Accepted Answer

__all__ = ['circle', 'square', 'triangle']. Option D is correct because the `__all__` variable in `__init__.py` explicitly defines the list of submodule names that should be imported when `from shapes import *` is executed. Setting `__all__ = ['circle', 'square', 'triangle']` tells Python to import only those submodules, which is the standard mechanism for controlling wildcard imports from a package.

Answer

Set __all__ to an empty list

Answer

__all__ = ['circle', 'square', 'triangle'] and import each submodule

Answer

Import each submodule in __init__.py without defining __all__

Question 15

Inside a package 'data', there is a subpackage 'io' and a module 'utils'. Which import statement inside the 'io' subpackage correctly imports the 'helper' function from the sibling module 'utils'?

Accepted Answer

from ..utils import helper. Option A is correct because the `..` prefix in a relative import refers to the parent package (`data`), and then `utils` is a sibling module of `io` within that parent package. This allows the `io` subpackage to import the `helper` function from the sibling module `utils` using `from ..utils import helper`.

Answer

import data.utils.helper

Answer

from .utils import helper

Answer

from data.io.utils import helper