PCAP Practice Test 8 — 10 Questions

Question 1

A developer needs to parse a log file where each line contains a timestamp followed by a message. The timestamp format is 'YYYY-MM-DD HH:MM:SS'. Which string method is most appropriate to split the timestamp from the message?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

str.split(). Str.split(), is the most appropriate because it splits a string on whitespace by default. Although the timestamp 'YYYY-MM-DD HH:MM:SS' contains a space, using split() without arguments returns a list of all space-separated elements. Since the timestamp is always the first two elements (date and time), the developer can join them with a space to get the full timestamp. Alternatively, split() can be used with a specified separator and maxsplit to achieve the desired split. This flexibility makes str.split() the best choice among the given options.

Answer

str.rsplit()

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str.splitlines()

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str.partition()

Question 2

A developer wants a class 'LoggedDict' that behaves like a dict but logs all attribute access in the console. Which method override correctly implements this for getting an attribute?

Accepted Answer

def __getattribute__(self, name): print(f'Access {name}'); return super().__getattribute__(name). `__getattribute__` is the universal method called for every attribute access on an object. By overriding it, the developer can log the attribute name before delegating to the superclass implementation via `super().__getattribute__(name)`, which preserves the normal attribute lookup chain. This ensures that all attribute accesses (including those that exist and those that don't) are logged, which is the requirement for 'LoggedDict'.

Answer

def __get__(self, instance, owner): print(f'Access'); return self

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def __getattr__(self, name): print(f'Access {name}'); return self.__dict__[name]

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def __getitem__(self, key): print(f'Access {key}'); return dict.__getitem__(self, key)

Question 3

A function receives a file path like '/home/user/docs/file.txt' and needs to return the path without the file extension, e.g., '/home/user/docs/file'. Which code reliably removes only the last dot extension, even if the directory names contain dots?

Accepted Answer

path.rsplit('.', 1)[0]. `rsplit('.', 1)` splits the string from the right, limiting the split to exactly one occurrence, which isolates the file extension (the part after the last dot) and returns everything before it. This reliably removes only the last dot extension, even if directory names contain dots, because it targets the final dot in the path.

Answer

path.split('.')[0]

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path.replace('.', '', 1)

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path[:path.find('.')]

Question 4

Refer to the exhibit. A developer is writing a script to read this JSON configuration file. The script should write the logging configuration to a separate file called 'logging.conf'. Which file mode should be used to create the file if it doesn't exist, and overwrite it if it does?

Accepted Answer

'w'. ('w') is correct because the 'w' mode opens a file for writing, truncating it first if it exists, and creating it if it does not. This matches the requirement to overwrite an existing 'logging.conf' file or create a new one if absent.

Answer

'x'

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'r+'

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'a'

Question 5

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.

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

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Sub1 should not have an __init__.py file.

Question 6

A developer tries to modify a string: s = 'hello'; s[0] = 'H'. What happens when this code runs?

Accepted Answer

It raises a TypeError: 'str' object does not support item assignment. Strings in Python are immutable, meaning their contents cannot be changed after creation. Attempting to assign a new character to an index position (e.g., s[0] = 'H') raises a TypeError: 'str' object does not support item assignment. To modify a string, you must create a new string using slicing or concatenation.

Answer

It changes the string to 'Hello'

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It creates a new string 'Hello' and assigns it to s

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It raises an IndexError because index 0 is out of range

Question 7

You are a DevOps engineer managing a Python application that consists of multiple microservices. One microservice, 'data_processor', imports a shared library 'common_lib' which is also used by other microservices. The shared library is developed in a separate repository and is installed via pip in each microservice's virtual environment as an editable package (pip install -e). Recently, you updated 'common_lib' with new functions, but when you redeploy 'data_processor' (by restarting the container), the new functions are not available; the old version is still used. The container uses a Docker image built from a requirements file that specifies 'common_lib' from a Git repository. You verify that the Git commit hash in the requirements file points to the latest version. What is the most likely cause and what is the correct course of action?

Accepted Answer

Update the commit hash or use a version tag that points to the latest, and rebuild the Docker image without using cache (--no-cache).. When a Docker image is built, pip installs the package from the Git repository at the commit hash specified in the requirements file. Even if the requirements file points to the latest commit, Docker's layer caching may reuse a previously built layer that contains the old version of the package. Rebuilding the image with --no-cache forces Docker to re-execute the pip install step, fetching the latest code from Git and installing the updated common_lib. Simply restarting the container does not rebuild the image, so the old installed package persists.

Answer

Add the common_lib source directory to sys.path in the microservice code.

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Rename the package in the requirements file to force a fresh install.

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Change the Python interpreter to a different version.

Question 8

A developer is building a logging system that writes logs to a file. The system should handle disk-full situations gracefully without crashing the main application. Which approach is appropriate?

Accepted Answer

Wrap the log write in a try/except that catches OSError and writes to stderr as fallback.. It uses a targeted try/except block around only the log write operation, catching OSError (which includes disk-full conditions) and falling back to stderr. This prevents the main application from crashing while still reporting the error, adhering to the principle of handling exceptions at the point where they occur and only when you can meaningfully recover.

Answer

Check disk space before each write; if low, skip logging.

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Wrap the entire application in a try/except that catches all exceptions.

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Let the OSError propagate to the main program's exception handler.

Question 9

A Python script fails with 'ModuleNotFoundError: No module named 'myapp.config''. The environment variable PYTHONPATH is not set. Which of the following is the most likely cause?

Accepted Answer

The module is located in a directory not included in sys.path. When PYTHONPATH is not set, Python relies solely on sys.path to locate modules. sys.path includes the script's directory, standard library paths, and site-packages. If 'myapp.config' is not in any of these directories, Python raises ModuleNotFoundError. Option A correctly identifies that the module is in a directory not included in sys.path.

Answer

The module's __init__.py is missing

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The module is installed in a different Python version's site-packages

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The module has a syntax error

Question 10

A package 'pkg' is installed as an egg-link in development mode. Inside the package, there is a module 'submod.py' that uses relative imports. When a developer modifies 'submod.py', they find that changes are not always reflected on import. What is the most likely reason?

Accepted Answer

Python's module caching in sys.modules prevents re-loading the modified source.. Python caches imported modules in `sys.modules`. When a module is imported, Python stores the module object in `sys.modules` and subsequent imports retrieve it from this cache without re-executing the module's code. Modifying the source file of `submod.py` does not automatically invalidate this cache, so the changes are not reflected unless the module is explicitly reloaded (e.g., with `importlib.reload()`) or the interpreter is restarted.

Answer

The sys.path is altered by the egg-link, causing a different module to be loaded.

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Relative imports are cached in the __init__.py file.

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The __pycache__ directory is not cleared automatically.