PCAP Modules and Packages Practice Test 5 — 15 Questions

Question 1

Refer to the exhibit. Given the project structure, which of the following import statements in main.py would cause an ImportError?

Accepted Answer

from ..utils import helpers. Uses a relative import with '..' which is only valid inside a package (i.e., when the module is loaded as part of a package and has a __package__ attribute set). In a flat project structure where main.py is a top-level script, '..' attempts to go above the top-level package, which is not allowed and raises an ImportError. Python's import system requires that relative imports be used only within a package hierarchy.

Answer

from utils import strings

Answer

from utils import helpers

Answer

from utils.strings import format

Question 2

A developer has a project structure with 'my_package/' containing '__init__.py', 'module_a.py', and 'sub_package/' (with its own '__init__.py'). They want to import function 'foo' from 'module_a' inside a script in 'sub_package' using a relative import. Which statement is correct?

Accepted Answer

from ..module_a import foo. The script is inside 'sub_package/', which is one directory level below 'my_package/'. To import from 'module_a' (located in the parent package 'my_package'), a relative import uses '..' to go up one package level, then specifies the module name. Thus, 'from ..module_a import foo' correctly navigates the package hierarchy.

Answer

from .module_a import foo

Answer

from my_package.module_a import foo

Answer

from ..my_package.module_a import foo

Question 3

A Python script uses a third-party library 'requests'. The developer wants to ensure that the exact version 2.25.1 is installed in the project's environment. Which tool and command should be used?

Accepted Answer

pip install requests==2.25.1. Both options B and C are correct because they use the standard pip syntax for pinning a specific version: `package==version`. The command `pip install requests==2.25.1` (B) works on systems where `pip` is linked to Python 3, while `pip3 install requests==2.25.1` (C) explicitly invokes the Python 3 version of pip. Both achieve the same result—installing requests exactly version 2.25.1. Option A fails to specify a version, and option D contains a typo ('instll') that will fail.

Answer

pip install requests

Answer

pip instll requests==2.25.1

Question 4

A developer is creating a Python package named 'utils' and wants to control what is imported when a user writes 'from utils import *'. Which file and variable should be defined?

Accepted Answer

Define __all__ = ['mod1', 'mod2'] in '__init__.py' of the 'utils' package.. In Python, the `__all__` variable in the `__init__.py` file of a package explicitly defines the list of module names that are exported when a user writes `from utils import *`. This controls the public API of the package and prevents unintended internal modules from being imported.

Answer

Define __all__ as a function that returns the list of modules in '__init__.py'.

Answer

Set the __all__ variable in the script that imports the package.

Answer

Define __all__ as a list of module objects in the main module 'utils.py'.

Question 5

A team is using a shared Python environment where multiple projects have conflicting dependencies. Which approach is the best practice to isolate project dependencies?

Accepted Answer

Create a virtual environment using 'python -m venv' and install dependencies inside it.. Using `python -m venv` creates an isolated virtual environment with its own `site-packages` directory, preventing dependency conflicts between projects. This is the standard best practice recommended by the Python Packaging Authority (PyPA) for managing project-specific dependencies without affecting the system-wide Python installation.

Answer

Manually modify sys.path in each script to include different package directories.

Answer

Install all dependencies in the system-wide site-packages directory.

Answer

Install all packages using 'pip install --user' to avoid system conflicts.

Question 6

A package 'mypkg' has the following structure:
mypkg/
  __init__.py
  submod1.py
  submod2.py
The __init__.py file contains: from . import submod1, submod2. A user runs 'import mypkg' and then 'mypkg.submod1.func()'. However, the user got an AttributeError. What is the most likely cause?

Accepted Answer

The submod1 module does not define a function named 'func'.. The AttributeError indicates that the attribute 'func' was not found on the module object 'submod1'. Since the import statement in __init__.py correctly makes submod1 accessible as mypkg.submod1, the only remaining reason for the error is that submod1.py does not define a function named 'func'. The import mechanism itself is working as intended.

Answer

submod1 is actually a package, not a module, so it cannot be called with 'func()'.

Answer

The __init__.py should use absolute imports like 'import mypkg.submod1' to make submod1 accessible.

Answer

The user must also run 'from mypkg import submod1' before accessing submod1.

Question 7

A developer wants to use a function 'calculate' from a module 'math_ops' that is located in a sibling directory '../shared/' relative to the current script. What is the correct way to import it using an absolute import assuming the shared directory is a package with __init__.py and the project root is in sys.path?

Accepted Answer

from shared.math_ops import calculate. Absolute imports in Python use the project root as the base, not relative paths. Since the project root is in sys.path, 'from shared.math_ops import calculate' directly references the 'shared' package at the top level, regardless of the current script's location. This is the standard absolute import syntax as defined in PEP 328.

Answer

from .shared.math_ops import calculate

Answer

from ..shared.math_ops import calculate

Answer

import ..shared.math_ops

Question 8

A Python package 'analytics' contains a subpackage 'models' with module 'regression.py'. Inside 'regression.py', there is a function 'linear_fit' that depends on 'numpy'. The developer wants to ensure that 'numpy' is imported only once and available throughout the package. Where should the import 'import numpy as np' be placed?

Accepted Answer

In each module that uses numpy, add 'import numpy as np'.. To use numpy in regression.py, that module must have its own import statement, e.g., 'import numpy as np'. Python caches modules in sys.modules, so loading happens only once regardless of where the import statement appears. Thus, repeating 'import numpy as np' in each module that needs it is both correct and efficient, and it respects namespace isolation.

Answer

In the '__init__.py' of the 'models' subpackage.

Answer

In the '__init__.py' of the 'analytics' top-level package.

Answer

In a separate file 'common_imports.py' and import that file everywhere.

Question 9

A developer runs the following code in a script that is not part of a package:
import sys
sys.path.insert(0, '/custom/path')
import mymodule
print(mymodule.__name__)
What is the output if 'mymodule' is found at '/custom/path/mymodule.py'?

Accepted Answer

mymodule. When a module is imported, Python assigns the `__name__` attribute to the module's name as a string (e.g., 'mymodule'), not the filename with extension. Since the script is not part of a package and the module is found at a custom path, `mymodule.__name__` is simply 'mymodule'.

Answer

mymodule.py

Answer

__main__

Answer

/custom/path/mymodule.py

Question 10

Which THREE of the following statements about Python's module search path are true?

Accepted Answer

The PYTHONPATH environment variable can be used to add custom directories to sys.path.. Option A is correct because PYTHONPATH is an environment variable whose directories are prepended to the default module search path, effectively extending sys.path so custom modules can be imported. Option C is correct because when a script is executed, Python automatically inserts the directory containing that script at the front of sys.path, allowing sibling modules to be imported. Option E is correct because sys.path is an ordinary Python list that can be modified at runtime (e.g., via sys.path.append() or sys.path.insert()) to alter where subsequent imports are resolved. Option B is wrong because PYTHONPATH directories are searched before site-packages, not after. Option D is wrong because the current working directory is not always the last entry in sys.path; its presence and position depend on how Python is invoked (for example, it appears first when running interactively or with -c/-m, and is not added at all when running a script).

Answer

The site-packages directory is searched before the PYTHONPATH directories.

Answer

The current working directory is always the last entry in sys.path.

Question 11

Which TWO of the following are valid uses for the '__name__' variable in a Python module?

Accepted Answer

To check if the module is being run as the main program.. The '__name__' variable is set to the string '__main__' when the module is executed directly as the main program (e.g., via 'python module.py'). This allows a module to include code that runs only when it is the entry point, not when it is imported by another module. The check is typically done with 'if __name__ == "__main__":'.

Answer

To get the file path of the module.

Answer

To control which names are exported when using 'from module import *'.

Answer

To determine which module imported it.

Question 12

A package 'mypackage' has subpackages 'sub1' and 'sub2'. In sub1/__init__.py, there is: from sub2 import helper. When importing mypackage, an ImportError occurs: No module named 'sub2'. What is the most likely cause?

Accepted Answer

The import should be from .sub2 import helper (relative import).. When a subpackage (sub1) tries to import from a sibling subpackage (sub2) using a bare name (from sub2 import helper), Python looks for 'sub2' as a top-level module, not as a sibling within the same parent package. Since 'sub2' is not installed as a top-level module, an ImportError occurs. Using a relative import (from .sub2 import helper) explicitly tells Python to look for sub2 as a sibling package under the same parent, resolving the import correctly.

Answer

Sub2 is not installed in the Python environment.

Answer

Sub2 must be imported before sub1 in the package's __init__.py.

Answer

Sub1 should not have an __init__.py file.

Question 13

A programmer wants to use the sqrt function from the math module. Which import statement is most efficient?

Accepted Answer

from math import sqrt. `from math import sqrt` binds only the `sqrt` function into the current namespace, avoiding name collisions with other math functions. While the `math` module itself is still fully loaded, this form avoids introducing extra global names and provides direct access to `sqrt`, which is more convenient and slightly faster than attribute lookup with `math.sqrt`. It is the most appropriate when only that one function is needed.

Answer

import math.sqrt

Answer

from math import *

Answer

import math

Question 14

A team uses virtual environments to manage dependencies. They need to ensure that a script runs with the exact same module versions across different environments. Which approach is best?

Accepted Answer

Run pip freeze and store the output in a requirements.txt file, then use pip install -r on other systems.. `pip freeze` outputs the exact versions of all installed packages in the current environment, and storing that output in a `requirements.txt` file allows you to reproduce the same environment on another system by running `pip install -r requirements.txt`. This ensures deterministic dependency management across different environments, which is the standard practice for reproducible builds in Python.

Answer

Use sys.path.append to add module directories.

Answer

Copy the entire virtual environment folder to other systems.

Answer

Include the modules in a __pycache__ directory.

Question 15

A module 'config.py' contains a variable 'settings' that is a dictionary. Another script does: from config import settings. Then the script modifies settings['key'] = 'new_value'. What happens?

Accepted Answer

The change is reflected in config.settings because it is the same object.. Python's import statement binds the name 'settings' in the importing module's namespace to the same dictionary object that exists in config.py. Since dictionaries are mutable, modifying settings['key'] directly mutates the shared object, and the change is visible through config.settings as well.

Answer

The config module is reloaded and the change is lost.

Answer

The script gets a copy of the dictionary, so config.settings is unchanged.

Answer

An error occurs because settings is read-only.