scenario questions

A developer is writing a function to reverse each word in a sentence while preserving the original order of the words. For example, 'Hello World' should become 'olleH dlroW'. The current implementation is: def reverse_words(s): return ' '.join(word[::-1] for word in s.split()). This works for simple cases. However, the input may contain multiple spaces between words (e.g., 'Hello World') and tabs. The requirement is to preserve the exact whitespace between words (including tabs and multiple spaces) in the output. Which of the following modifications will achieve this while keeping the approach efficient?

Refer to the exhibit. What happens when the code is executed?

Given the following code: class Parent: def show(self): print('Parent') class Child(Parent): def show(self): print('Child') c = Child(); c.show(); super(Child, c).show(). What is the output?

A parent class defines a method `move()`. A child class overrides `move()` but also needs to call the parent's version inside it. Which syntax allows that?

A QA engineer needs to verify that a user input string contains at least one uppercase letter, one lowercase letter, and one digit. Which regex pattern can be used with re.search() to achieve this?

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'?

A junior developer writes a class 'Logger' that should only ever have one instance (singleton). They attempt to implement it by overriding __new__ to always return the same instance. However, when multiple threads attempt to create a Logger, they sometimes get different instances. Which modification will make the singleton thread-safe?

Which THREE of the following are immutable types in Python?

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?

What happens when you execute the following code? s = 'hello'; s[0] = 'H'

A programmer needs to write a function that reads a large binary file (over 1 GB) and returns its entire content as a bytes object. The function must handle the case where the path provided is actually a directory (IsADirectoryError) by returning an empty bytes object. Which implementation is most memory-efficient and correctly handles the directory case? Consider that reading the entire file into memory is acceptable for the business case.

A junior developer is parsing a log file where each line has comma-separated fields. However, some fields are enclosed in double quotes and contain commas inside, e.g., '2023-08-15 14:30:00,WARNING,"Disk space low, please clean up".'. They are required to parse these lines using only built-in string methods (no modules like csv or re). Which approach is the most reliable and efficient?

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?

Refer to the exhibit. What is the output? (Note: actual MRO may vary; choose the one that matches Python 3 C3 linearization.)

Which method of a file object reads the entire content of a text file as a single string?

Drag and drop the steps to handle an exception in Python using try-except-finally into the correct order.

A script contains the following lines: import math from math import sqrt print(math.sqrt(16)) print(sqrt(25)) What is the output when the script is executed?

Drag and drop the steps to define and call a function with default arguments in Python into the correct order.

A programmer writes a class with a method that should be called on the class itself, not on instances. Which decorator is appropriate?

A company runs a data processing pipeline that reads CSV files from a network drive. Occasionally, the network drive is unreachable causing FileNotFoundError. The current code uses a bare except clause that catches all exceptions, which also masks programming errors like NameError. The lead developer wants to implement a more robust exception handling strategy. The requirement is to log the specific error (including the filename) and retry the operation up to 3 times with a 2-second delay between retries. If after 3 attempts the file is still inaccessible, the pipeline should skip the file and continue with the next one. Which approach best meets these requirements?

You are a network engineer troubleshooting a script that processes router configuration files. The script reads a configuration line from a file: 'interface GigabitEthernet0/1 ip address 192.168.1.1 255.255.255.0 no shutdown'. The script needs to extract the interface name and IP address. The current code uses string split operations but fails when the line has extra spaces or tabs. For example, when the line is 'interface GigabitEthernet0/1', the split returns ['interface', '', '', 'GigabitEthernet0/1'] and the script fails. You need to modify the script to robustly extract the interface name and IP address regardless of whitespace. Which approach should you take?

A team is developing a large application and wants to organize code into packages. Which of the following is a best practice for package design?

What is the cause of the error?

A class 'MyClass' has a method 'do_something' that uses 'self.__private'. A subclass 'MySubClass' tries to access 'self.__private' and gets an AttributeError. Why?

Consider the following code: print(type('apple,banana,cherry'.split(','))) What type of value is printed?

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?

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?

A developer wants to ensure that an attribute 'balance' of a BankAccount class cannot be accessed directly from outside the class but can be accessed through a method. Which approach should be used?

A developer designs a plugin system where each plugin must implement a method 'execute'. Which code snippet correctly enforces that subclasses provide an implementation using the 'abc' module?

A log processing script receives a multiline string log. The script needs to check if the string ends with the substring 'ERROR'. Which method should be used?

A developer needs to write a function that safely divides two numbers and returns None if division by zero occurs. Which implementation is most Pythonic?

Which TWO statements about exception handling in Python are correct? (Select exactly 2.)

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

Match each Python data structure to its mutability.

You are a developer at a company that processes customer feedback. Each feedback entry is stored as a string containing a rating (1-5) followed by a colon and then the comment. For example: '4: Great service'. You need to extract only the comments from feedback that have a rating of 4 or 5. You have a list of feedback strings. Which code snippet correctly implements this?

What is the result of 'PyThon'.lower()?

A data pipeline processes CSV lines that may contain quoted fields with commas inside double quotes. For example: 'John, "Doe, Jr.", 35'. The team needs to split such a line correctly. Which approach is best?

What is the result of the expression 'Hello' * 3?

Which THREE of the following string methods return a boolean value (True or False)? (Choose exactly 3 correct answers.)

What is the output of the following code? try: exec('1/0') except: print('error') else: print('no error') finally: print('done')

Which of the following is the BEST practice for building a large string by concatenating many smaller strings in Python?

Refer to the exhibit. What is printed?

A developer opens a CSV file with open('data.csv', 'r', encoding='utf-8') and reads it with readline(). The first line contains a non-ASCII character that the file declares as UTF-8. Which exception is most likely raised if the file actually contains bytes that are not valid UTF-8?

Refer to the exhibit. Which of the following fixes the error?

A developer notices that a custom package 'mypackage' is not being found when importing, even though it is installed in the site-packages directory. The developer suspects a conflict with another package of the same name. Which command should the developer run to diagnose the location from which Python is importing the package?

A developer has a function that performs several operations and may raise different exceptions. The developer wants to catch a specific exception and then re-raise it after logging. Which code snippet correctly re-raises the same exception without losing its traceback?

A developer has a module 'config.py' with the following content: # config.py import os DATABASE_URL = os.getenv('DATABASE_URL', 'localhost') Another module 'app.py' imports config and uses DATABASE_URL. During testing, the environment variable is set correctly, but the import still uses the default value 'localhost'. What is the most likely reason?

Which TWO statements are true regarding strings in Python?

A data analyst is cleaning a CSV file. They have a string variable containing a row of data: 'John,Doe,30,New York'. They need to extract the last name 'Doe' using string methods. The analyst writes: name = row.split(',')[1]. However, they are concerned about performance because the file contains millions of rows. They want to use a more efficient method that extracts the substring without creating a full list. Which approach should the analyst use?

Given that MyClass defines __private_attr in __init__, why does this error occur?

A developer writes a helper that copies lines from one text file to another. The helper opens both files with open() inside a try block and closes them in a finally block. If an exception occurs while writing, which statement about the finally block is correct?

A developer writes code to display a floating-point number with exactly two decimal places. Which f-string expression is correct for value = 3.14159?

You are a developer for a data science team. The team uses a shared module 'utilities' located at /team/shared/utilities.py. This module is not part of any package, and they want to import it from various project scripts without copying the file. Some projects are in /home/user/proj_A/ and others in /var/data/proj_B/. Currently, each script manually adds /team/shared/ to sys.path using sys.path.insert(0, '/team/shared/'). This works but is repetitive. The team wants a cleaner solution that also works when the script is run from different working directories. They consider creating a package 'utilities' by adding an __init__.py to the directory and using relative imports. However, the module currently uses absolute imports for some external libraries. What is the best course of action to allow clean imports of utilities from any location while minimizing changes to the module itself?

A developer wants to replace all vowels in a string with their corresponding uppercase letters. They wrote: `s = 'hello world'`; `vowels = 'aeiou'`; `trans = str.maketrans(vowels, vowels.upper())`; `result = s.translate(trans)`. What is the value of `result`?

Which THREE of the following exception types are subclasses of OSError in Python 3?

A programmer wants to check whether a string `s` is a palindrome (reads the same forwards and backwards, ignoring case and non-alphanumeric characters). Which code snippet correctly implements this?

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?

You are developing a high-performance logging module that must handle thousands of log entries per second. Each entry is built by concatenating a timestamp, level, and message. Currently, your code uses a loop that repeatedly appends to a string using the += operator. This results in high memory usage and sluggish performance because each concatenation creates a new string object. The module must run on systems with limited memory and cannot rely on external libraries. Which course of action would best resolve the performance issue while maintaining readability and standard library compliance?

A Python project has the following directory structure: project/ __init__.py main.py subpackage/ __init__.py module.py Inside 'module.py', there is a function 'func' that needs to be imported in 'main.py'. The team wants to import 'func' using a relative import from 'main.py'. However, when they run 'python main.py' from the project root, they get an ImportError. What is the most likely reason?

Which TWO string methods are used to determine if a string begins or ends with a specified prefix or suffix? (Choose two.)

Refer to the exhibit. What will be the output when the code is executed?

A developer is writing a function that reads a configuration file. The function must distinguish between a missing file, a permission problem, and a malformed file, and it must not leave the file open on any path. Which TWO techniques are appropriate for this requirement? (Choose two.)

A programmer wants to restrict a class to only allow specific attribute names and reduce memory usage. Which feature should they use?

Which TWO statements about the 'from package import *' statement are correct?

Match each code snippet to its output.

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?

Which THREE factors can cause an 'ImportError' when trying to import a module?

A script reads a binary file and decodes it as UTF-8. Some bytes are invalid UTF-8 sequences, causing a `UnicodeDecodeError`. The developer wants to replace invalid bytes with the replacement character U+FFFD. Which approach achieves this?

A Python script reads a file containing text with non-ASCII characters like 'é' and 'ü'. The script must encode the string as UTF-8 then decode it back. Which of the following correctly handles this without error?

A developer creates classes `A`, `B(A)`, `C(A)`, and `D(B, C)`. When calling a method from `D` that is defined in `A`, which class's version is used according to Python's MRO?

Refer to the exhibit. What happens when the last command is executed?

A developer wants to check if a string 'example.txt' ends with '.txt'. Which expression returns True?

A user wants to ensure that a custom module 'mymod' located at '/home/user/custom' takes precedence over a standard library module with the same name. Which operation on sys.path should be performed?

What is the most likely cause of this error?

A team is using f-strings to format a report. They have a variable `value = 0.123456789` and want to display it with exactly 3 significant digits. They write `f"{value:.3g}"`. The output is '0.123'. They expected '0.123'. Is the output correct? If not, what change would produce '0.123'?

A developer is designing a class hierarchy for a library system. They want to ensure that a method 'borrow' in the base class 'Item' can be overridden by subclasses like 'Book' and 'DVD', but the base implementation should not be callable directly. Which approach best achieves this?

A network engineer processes a configuration file containing MAC addresses in the format 'aa:bb:cc:dd:ee:ff'. They need to convert each MAC address into a 6-byte bytes object for use in packet crafting. The current code is: mac_bytes = bytes([int(x, 16) for x in mac_str.split(':')]). This works correctly, but they need to process thousands of MAC addresses and want to optimize performance. They also need to handle invalid MAC addresses (e.g., non-hex characters) without crashing. Which of the following approaches is the most efficient and robust?

A developer generates a report where numbers must be right-aligned in a 10-character column using f-strings: f'{value:>10}'. However, some values may be None, causing a TypeError. Which is the most robust way to handle None values without affecting other falsy values like 0?

What will be printed?

Which of the following statements about the `finally` block is true?

A developer wants to create a class that logs every attribute access on an instance. Which special method should they override?

What does the expression 'hello world'.title() return?

Match each string method to its purpose.

A Python script that processes log files uses the following code: with open('log.txt', 'r') as f: lines = f.readlines() for line in lines: # process What is a potential inefficiency in this code?

A class defines an __init__ method that takes optional arguments. What is the correct way to provide default values?

What is the value of matches?

Which TWO of the following statements about Python classes are true? (Select exactly 2.)

A junior developer is writing a helper that reads a small log file and returns its contents as a single string. The file is guaranteed to exist and be readable. The helper currently uses an explicit open, a try/finally block, and manual close call. A reviewer asks for the most idiomatic Python 3 replacement that guarantees closure. Which construct should be used?

Which of the following is a correct use of the @property decorator to create a getter and setter for an attribute named 'score' that ensures score stays between 0 and 100?

Which TWO of the following string methods return a new string with all characters converted to lowercase? (Select exactly two.)

A class `Circle` has a class attribute `pi = 3.14`. An instance `c = Circle()` sets `c.pi = 3.14159`. What is the value of `Circle.pi` after this assignment?

A class has both `@classmethod` and `@staticmethod` decorators. What is a key difference between them?

A senior developer in a team argues that using try-except blocks is slower than checking conditions with if statements. They propose replacing all try blocks that handle file I/O errors with existence checks using os.path.exists before opening files. During a code review, you recall that Python's official documentation and best practices prefer EAFP (Easier to Ask for Forgiveness than Permission) over LBYL (Look Before You Leap) in many cases, especially in concurrent environments. The team's application is a multi-threaded web server that serves static files from a shared directory. Which is the strongest counterargument against the senior developer's proposal?

Which THREE of the following are true about Python strings?

What is the result of 'abcdef'[::-2]?

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?

Drag and drop the steps to create and activate a virtual environment in Python into the correct order.

During development, a programmer modifies a module that is already imported in the current Python session. To see the changes without restarting the interpreter, which function from the importlib module should be called?

Refer to the exhibit. Which of the following Python code snippets would generate this error?

Which of the following correctly uses `__slots__` to restrict attribute creation to only `x` and `y`?

A developer needs to replace all occurrences of 'cat' with 'dog' in a string, but only if 'cat' is a whole word (not part of 'category'). Which code achieves this?

A developer is working with a string `text = "The quick brown fox jumps over the lazy dog"`. They want to create a new string where every occurrence of the word 'the' (case-insensitive) is replaced with 'a'. However, they must not replace 'the' when it is part of another word, such as in 'then' or 'there'. Which approach correctly achieves this?

A developer wants to convert a string 'Python' to all uppercase letters. Which string method should be used?

Which TWO of the following are correct statements about the 'with' statement in Python file I/O?

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

A class defines a variable `count = 0`. An instance modifies `self.count = 5`. What is the value of `count` in the class namespace?

A developer wants to create a string that contains the current year and month in the format 'YYYY-MM'. The year and month are stored in integer variables year and month. Which expression would produce the desired result?

What is the output of `print('-'.join(['a', 'b', 'c']))`?

A cloud infrastructure engineer is developing a Python script to parse large configuration files from a fleet of servers. Each file can be up to 500 MB. The script reads the file line by line using a file object, strips comment lines (those starting with '#'), and accumulates only the configuration directives into a single string for further processing. The current code is: ```python result = '' with open('config.cfg') as f: for line in f: if not line.startswith('#'): result += line.strip() ``` After processing just a few hundred lines of a large file, the script becomes extremely slow and consumes an excessive amount of memory. The engineer identifies that string concatenation using `+=` is inefficient because strings are immutable, causing repeated memory reallocation. Which approach should the engineer implement to resolve the performance issue without changing the final output?

A developer writes a script to read a configuration file that may not exist. The script should handle the error gracefully and continue. Which approach is most Pythonic?

A subclass overrides a method but wants to call the parent class's version. Which keyword should be used?

You are developing a package 'analytics' that contains subpackages 'stats' and 'ml'. The __init__.py of 'analytics' imports a function 'normalize' from 'analytics.stats'. When a user runs `import analytics`, they get an ImportError. Which change ensures the package imports correctly?

Match each Python operator to its precedence level (1=highest).

A team is developing a data processing pipeline where each step is a class that implements a common interface. They have defined an abstract base class DataProcessor with an abstract method process(data). Several concrete subclasses implement process. Now they need to add a new step that logs the data before processing. They want to reuse the existing processing logic without modifying the original classes. Which design pattern should they apply?

A company has a shared internal library stored in a Git repository. Developers need to use this library in multiple projects without copying the code. Which approach is the most Pythonic and maintainable?

A developer is building a large string by concatenating many substrings in a loop using '+'. What is the main performance issue?

A developer defines a class with an __init__ method that sets instance attributes. Which of the following is the correct way to call the parent class's __init__ from a child class?

Match each Python module to its purpose.

Consider the code fragment: f = open('data.txt', 'r') data = f.read() process_data(data) f.close() What is the primary risk if an exception occurs during process_data(data)?

Which TWO of the following are true about the 'with' statement in Python file I/O?

Which three statements about the Method Resolution Order (MRO) in Python are true? (Choose three.)

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?

A programmer writes a function to check if a string is a palindrome (ignoring case and non-alphanumeric characters). Which implementation correctly achieves this?

A developer wants a class 'Point' to have a readable string representation that returns 'Point(x, y)'. Which special method should be overridden?

A developer writes a class 'Logger' with a class method 'log(msg)' that writes to a file. Another class 'AppLogger' inherits from 'Logger'. The developer expects both classes to share the same file handle. However, after creating an instance of 'AppLogger', the file handle is different. What is the most likely cause?

An engineer is debugging an application that uses inheritance. The base class 'Vehicle' defines a method 'start()' that prints 'Vehicle started'. The subclass 'Car' overrides 'start()' to print 'Car started'. The code contains a function that accepts a Vehicle object and calls 'start()'. What is the output if a Car object is passed?

In Python, if you have a try block followed by an except clause that catches all exceptions, which of the following is true about the else clause?

What is the output of the code?

A developer creates a package named 'mypkg' with an __init__.py file. Inside the package, there is a module 'utils.py'. Which of the following is the correct way to import the function 'helper' from 'utils' from outside the package?

A programmer uses a class method to create an alternative constructor for a `Point` class. The method should parse a string like "10,20" and return a `Point` instance with x=10, y=20. Which code snippet correctly implements this?

Match each exception to its cause.

A developer is cleaning data from a CSV file. They have a string `record = "John,Doe,35,Engineer"` and want to replace all commas with semicolons. However, they also want to ensure that any leading or trailing whitespace in the entire string is removed before the replacement. Which expression produces the desired result?

A developer wants to remove all leading and trailing whitespace from a string, but preserve internal spaces. Which line of code accomplishes this?

Which TWO methods are valid ways to import a function named 'foo' from a module 'bar' that is part of a package 'pkg'?

Refer to the exhibit. If both data.txt and backup.txt do not exist, what is the output?

Given s = 'Python', which THREE of the following expressions evaluate to True? (Choose three.)

A beginner programmer writes: name = "Alice"; print("Hello " + name). Which string method alternative is more efficient and recommended for Python 3?

A developer is building a simulation of different types of vehicles. They have a base class Vehicle with an attribute speed initialized in __init__. They also have a subclass Car that inherits from Vehicle and adds an attribute fuel_type. The developer wants to ensure that every time a Car object is created, it also initializes the speed attribute from the Vehicle class. Which approach should the developer use?

A developer is designing a system where a `Car` class needs to reuse functionality from `Engine` and `Transmission` without creating a deep hierarchy. Which OOP principle should be applied?

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?

A developer creates a Python class with a method that is intended to be overridden in subclasses. Which approach best ensures that the method is not accidentally called on the base class?

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?

A developer uses the .index() method on a string to find the position of a substring. If the substring is not found, what exception is raised?

A developer needs to combine a list of 10,000 strings into a single string. Which approach is most efficient in terms of memory and performance?

A developer wants to check if a string contains only alphabetic characters. Which string method should be used?

You are working on a legacy system that processes financial transactions. The system uses a class hierarchy: Transaction (base), Deposit, Withdrawal, Transfer. Each subclass overrides a method 'process()' to handle its specific logic. The code often runs in a multi-threaded environment and you notice intermittent errors where a transaction is processed twice. The logging shows that the same transaction object is being passed to the process method multiple times. The transaction objects are created from a factory function that caches recently used transactions. The errors seem to occur when two threads call the factory at the same time with the same parameters. After investigating, you find that the factory uses a class-level dictionary to cache objects. Which of the following is the most appropriate solution to prevent double processing?

Which TWO of the following methods return a boolean value?

Which TWO of the following statements about class attributes in Python are true?

A company is developing a scientific simulation framework where many different solvers must be interchangeable. The framework should enforce that each solver implements methods 'initialize' and 'step'. Developers want to use abstract base classes. Which approach should the team take to ensure that any subclass of 'Solver' cannot be instantiated unless it defines both methods?

A development team is building a real-time chat application using Python. The application uses a class 'ChatRoom' that maintains a list of 'User' objects as active participants. Each User object holds a reference back to its ChatRoom to send messages. Over time, the application runs out of memory. Profiling reveals that User objects are not being garbage collected even after users disconnect. The team suspects circular references. Which solution would effectively resolve the memory leak without breaking the functionality?

Your company has two separate Python packages: 'app' and 'lib'. They are maintained by different teams. 'app' depends on 'lib', but 'lib' is still under development and its API changes frequently. To avoid breaking 'app', the team decides to use a virtual environment and install a specific version of 'lib'. However, during development, they need to test 'app' with the latest 'lib' changes from the Git repository. The current workflow is: (1) activate virtual env, (2) install 'lib' from local source using `pip install -e /path/to/lib`. This installs 'lib' as a development package. But one developer reports that after pulling latest 'lib' changes, importing 'lib' in 'app' still uses the old version even after re-running pip install -e. What is the most likely reason?

A data entry application reads a CSV file where each line contains fields separated by commas. However, some fields are enclosed in double quotes and contain commas inside, e.g., 'John,"Doe, Jr.",30'. The developer currently uses line.split(',') to parse each line, which incorrectly splits the quoted field. The developer wants a solution using only the Python standard library (no third-party packages). Which of the following is the best approach?

A class `Point` has an `__init__` that sets `self.x` and `self.y`. They want to compare points by equality (i.e., `p1 == p2` should work correctly). Which method should they implement?

Which of the following correctly uses an abstract base class to enforce that all subclasses implement a 'make_sound' method? (Assume ABC imported)

Which method returns the lowest index where a specified substring is found, or -1 if not found?

A programmer is writing a script to generate SQL queries safely. They need to escape single quotes in user-provided strings to prevent injection. Which approach is most robust?

Which TWO of the following are special methods in Python?

Refer to the exhibit. A developer runs 'pip install pandas==2.0.0' but gets an error stating that the required version is not available. Which command should be used to list all available versions of pandas?

Given s = 'Python', what is s[1:4]?

A developer is writing a script that processes user-uploaded CSV files. The script should attempt to read the file, and if a UnicodeDecodeError occurs, log a warning and skip the file. Which code snippet correctly achieves this without stopping the entire process?

A developer writes a log message with variables: name = 'Alice' and age = 30. Which of the following uses an f-string correctly?

Refer to the exhibit. What is the effect of using 'from None' in the raise statement?

A production script opens a configuration file with `open('config.ini', 'r')`. During a recent maintenance window, the file was replaced by a directory of the same name. The script now terminates with `IsADirectoryError`. The developer wants to catch this specific condition separately from a missing file and log a distinct message. Which `except` clause should be added?

Consider the following code: name = "Alice" age = 30 print(f"{name} is {age} years old.") What is the output of the above code?

Given: class A: def method(self): print('A'); class B(A): def method(self): super().method(); print('B'); class C(A): def method(self): super().method(); print('C'); class D(B, C): pass. What is printed by D().method()?

Which TWO of the following string methods return a boolean value (True or False)?

Which TWO string methods raise an exception when the searched substring is not found?

Which TWO statements about Python strings are correct? (Choose exactly 2 correct answers.)

Which TWO of the following statements about Python packages are true?

A developer wants to check if a string 'racecar' is a palindrome by comparing it to its reverse. Which code completes the task correctly?

A developer needs to check if a string contains only alphanumeric characters. Which string method should be used?

Which of the following correctly raises a new exception while preserving the original traceback?

A developer is tasked with validating user input that must be a 10-digit phone number. The input may contain spaces, dashes, and parentheses. Which approach best ensures the input contains exactly 10 digits?

What is the likely outcome of running the following code? ```python with open("C:\Users\path\file.txt", "r") as f: print(f.read()) ```

Which TWO of the following are valid ways to import specific names from a module?

A developer is creating a custom exception hierarchy for a library. The base exception is `LibraryError`. Which definition ensures that subclasses can be caught using the parent exception, but also allows distinguishing between different error types?

You are a data analyst working with a dataset of customer reviews. Each review is stored as a string in a list. You need to count how many reviews contain the word 'excellent' (case-insensitive). However, the word might appear as 'Excellent', 'EXCELLENT', or even with punctuation like 'excellent!'. The current code uses 'excellent' in review.lower(), but this fails if 'excellent' is part of another word like 'unexcellent'. You need to ensure that only the whole word 'excellent' is counted. Which code modification will correctly count whole word occurrences?

Which three of the following statements about Python strings are true? (Choose three.)

What is the output of the code in the exhibit?

A developer is working on a project that requires the use of a third-party package hosted on a private repository. The developer wants to ensure that the package can be imported without specifying the full repository URL each time. Which approach should be taken?

Which of the following is the correct way to open a file for writing in binary mode?

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?

A junior developer is writing a script that processes user input. The script reads a line of text from the console and needs to remove any leading or trailing whitespace. The developer uses the strip() method but notices that it also removes other characters like newline. However, the requirement is to remove only spaces (not tabs or newlines). Which course of action should the developer take to remove only leading and trailing spaces?

Given the code: s = 'Python'; t = s; s = s + '3.0'. What is the value of t after these lines execute?

A Python script imports the module 'my_module'. The developer wants to ensure that when the script is run directly, it executes a specific function, but when imported as a module, that function is not executed. Which code snippet achieves this?

Which TWO of the following are built-in exceptions in Python? (Select exactly 2.)

What is the output of the Python code after reading the config.txt file?

What is the output?

A developer needs to count the number of occurrences of the substring 'is' in the string 'This is a test. Is this a test?'. Which code correctly performs the count?

Consider the following code: import json try: with open('config.json') as f: data = json.load(f) except FileNotFoundError: print("Missing config file") except json.JSONDecodeError: print("Invalid JSON") except: print("Unexpected error") If the file 'config.json' exists but contains invalid JSON, what is printed?

Which THREE are valid ways to create a multiline string in Python?

Refer to the exhibit. What is the output?

Which TWO of the following are valid ways to define a property in a Python class? (Select exactly 2.)

Which of the following expressions returns True if the string s contains only hexadecimal digits (0-9, a-f, A-F)?

A developer runs a script that reads records from a binary file. After a partial read, the storage device is unplugged, and the read() call raises OSError. The developer wants the script to retry the read a few times before giving up, but only for this transient I/O problem. Which exception should be caught to retry specifically on this failure?

An application needs to dynamically load a module whose name is provided at runtime (stored in a variable 'mod_name'). Which function from the importlib module should be used?

Which THREE statements about the Python method resolution order (MRO) are true? (Select exactly 3.)

Match each Python built-in function to its description.

A developer is formatting a log message and wants to ensure that a string variable `name` is centered within a field of width 20, padded with asterisks (`*`) on both sides. For example, if `name = "Alice"`, the result should be `*******Alice********` (7 asterisks on the left, 8 on the right). Which method call achieves this?

Which TWO statements about static methods (@staticmethod) are correct?

Given s = 'a1b2c3', which TWO of the following expressions return the string '123'?

A company has a large Python application that uses multiple packages from different directories. The application's main entry point is at /opt/app/main.py. There is a package 'common' located at /opt/app/common/ and another package 'services' at /opt/app/services/. Both packages have __init__.py files. Additionally, there is a third-party package 'utils' installed in the system site-packages. Recently, a developer added a new module 'helpers.py' to the 'common' package. When trying to import 'common.helpers' from a script inside 'services', an ImportError is raised: 'No module named common.helpers'. However, importing 'common' itself works. The sys.path includes /opt/app/ and the site-packages. What is the most likely cause of the import failure?

Which THREE of the following are true about Python's object-oriented programming features?

A developer creates a package 'mypackage' with the following structure: mypackage/ __init__.py module1.py module2.py The __init__.py contains: from mypackage.module1 import func1 from mypackage.module2 import func2 __all__ = ['func1', 'func2'] In a separate script, the developer writes: from mypackage import * print(func1()) This works as expected. However, when the developer runs the same script from a different directory (not the one containing mypackage), the import works but the script prints an error that func1 is not defined. What could be the problem?

A data-import tool must read a UTF-8 CSV file that occasionally contains bytes invalid for UTF-8. The tool should not crash, but it must record that replacement occurred so the operator can review the source. The developer opens the file with `open('data.csv', encoding='utf-8', errors='replace')` and reads it. Which outcome matches this configuration?

Which THREE of the following are true about Python's exception hierarchy?

A developer wants to distribute a package that contains both Python code and data files (e.g., images, configs). Which file is used to specify dependencies and metadata for the package?

Which TWO of the following can be used to remove leading whitespace (spaces, tabs, newlines) from a string? (Choose exactly 2 correct answers.)

Which of the following statements about class inheritance in Python are true? (Choose two.)

A developer is implementing a simple counter class. The class should start at 0 and increment by 1 each time the 'increment' method is called. Which implementation is correct?

When importing a module, Python searches for it in a specific order. Which of the following lists the correct order of directories searched?

Which TWO of the following statements about Python's `sys.path` are true?

A developer wants to remove leading and trailing whitespace from a string. Which method should be used?

A programmer wants to ensure that a class attribute is the same for all instances and can be accessed via the class name. Which type of variable should be defined?

A team is developing a banking system in Python. They have a base class Account with attributes account_number and balance, and a method __init__(self, account_number, balance) that initializes these attributes. They then create a subclass SavingsAccount that adds an attribute interest_rate. In SavingsAccount's __init__, they assign self.interest_rate = rate but do not call super().__init__. When they instantiate SavingsAccount('12345', 1000, 0.02) and attempt to print(balance), an AttributeError occurs: 'SavingsAccount' object has no attribute 'balance'. What is the most appropriate fix to ensure that the SavingsAccount includes balance and account_number without code duplication?

A Python package 'mypackage' contains the following hierarchy: mypackage/ __init__.py subpackage1/ __init__.py module_a.py subpackage2/ __init__.py module_b.py From a script outside the package, a programmer writes: import mypackage.subpackage1.module_a Which statement is true about the import?

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

Which of the following is the correct way to format a string to include a variable value with two decimal places in Python?

Which of the following is a valid way to import a module named 'math' and assign it an alias 'm'?

A developer needs to check if a filename starts with the prefix 'report_'. Which string method should be used?

Which TWO of the following string methods return a boolean value?

A team wants a `Logger` class that can be used both as `Logger.log('msg')` on the class itself and as `logger.log('msg')` on an instance, with identical behaviour and no access to instance state. Which decorator should be applied to `log`?

A developer wants to import a specific function 'calculate' from a module named 'formulas' without importing the entire module. Which import statement should be used?

An abstract base class (ABC) defines an abstract method `process()`. Several subclasses implement it. A function accepts any subclass and calls `process()`. This demonstrates which OOP concept?

When should you raise a specific exception class rather than a generic Exception?

An application uses a class to represent a configuration object that reads settings from a file. The class has a class attribute config_cache that holds a dictionary of loaded configurations to avoid repeated file reads. However, the developer notices that when they modify the dictionary for one instance, it affects all instances. They want to ensure that each instance has its own copy of the configuration data upon initialization. Which change should they make?

A developer wants to ensure that a class attribute is shared among all instances but cannot be modified from outside the class. Which approach is most appropriate?

A user runs script.py and gets the above error: ModuleNotFoundError: No module named 'mypackage'. Which of the following is the most likely cause?

Which THREE of the following are true about the `with` statement for file handling?

A file is opened with open('test.txt', 'r'). The file object's tell() method returns 0. After reading 10 characters, what does tell() return?

A backup utility writes a manifest with `with open('manifest.txt', 'w') as out:`. The developer needs to ensure that partial writes are not silently left in the file when an exception occurs mid-loop. Which two statements about using a try/except/else/finally structure around this write loop are correct? (Choose two.)

Which TWO statements about namespace packages are true?

A team is implementing a shape hierarchy with a base class `Shape` that should have an `area()` method. They want to ensure that every subclass must provide its own implementation of `area()`. Which approach should they use?

Consider a class `D` that inherits from multiple base classes `B` and `C`. The developer wants to call a method from a specific parent class while ensuring correct method resolution order (MRO). Which is the safest way?

You are a developer for an e-commerce platform. The system receives product descriptions from suppliers in various formats. One supplier sends descriptions with inconsistent capitalization, extra whitespace, and occasional leading/trailing punctuation. Your task is to write a function that normalizes these descriptions: convert to lowercase, remove leading/trailing whitespace and punctuation (.,!?;:), and replace multiple spaces with a single space. The function should return the cleaned string. Which implementation correctly performs all these steps?

A programmer writes a class with a static method using @staticmethod. What is the primary purpose of using a static method instead of a class method or instance method?

A programmer writes a context manager to manage a temporary file. The class implements __enter__ to open the file and return the handle, and __exit__ to close it. During the with body, an exception is raised. The programmer wants the exception to propagate after cleanup. What should __exit__ return in this case?

Given package structure: pack/__init__.py, pack/subpack/__init__.py, pack/subpack/mod.py. Inside pack/__init__.py, which import statement correctly imports mod.py using a relative import?

A programmer has a string 'apple,banana,orange' and wants to get a list ['apple', 'banana', 'orange']. Which method should be used?

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?

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

A programmer has a string s = 'Python programming is fun'. They want to extract the word 'programming'. Which slicing expression achieves this?

A developer writes a class `Vector` and wants `v1 + v2` to return a brand-new `Vector`, while `v1 += v2` should mutate `v1` in place and return it. Which pair of special methods achieves this behaviour?

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?

Drag and drop the steps to perform unit testing with the unittest framework in Python into the correct order.

A logging module receives a message that may contain sensitive data. To comply with data privacy, all digits in the message should be replaced with 'X' before logging. Which approach correctly achieves this?

Which THREE of the following statements about Python's 'with' statement are true? (Select exactly 3)

Drag and drop the steps to serialize a Python object to JSON using the json module into the correct order.

What is the result of the expression 'aBc'.lower()?

A script uses `with open('data.bin', 'rb') as f:` to read binary data. Within the block, which method should be used to read exactly 4 bytes?

A developer is working on a class hierarchy for geometric shapes. They have a base class Shape with an abstract method area(). They also have a mixin class Drawable that provides a method draw(). They want to create a class Rectangle that inherits from both Shape and Drawable. However, they encounter a TypeError when trying to instantiate Rectangle because the abstract method area() is not implemented. Which action should they take to resolve this?

Which THREE of the following are true about the `__init__` method in Python?

A programmer needs to replace every occurrence of 'cat' with 'dog' in a string s, but only if 'cat' is not preceded by 'big'. Which regex substitution would achieve this?

What is the output of the following code? try: print(1/0) except: print('err') finally: print('fin')

What is the output of 'hello'.count('l')?

Which of the following demonstrates that strings are immutable?

A developer defines a class 'A' with a method 'm' that uses 'self.a'. Class 'B' inherits from 'A' and defines __init__ that sets 'self.a = 10'. An instance of B is created and method m is called. What is the output?

A class `Vector` defines `__add__` to return a new `Vector`. A developer writes `v1 = Vector(1,2); v2 = Vector(3,4); v3 = v1 + v2`. What is the type of `v3`?

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?

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

Which TWO statements about the sys module are true?

What is the result of 'Python'.find('th')?

A developer writes a function that reads a file and processes its content. The function should handle the case where the file does not exist without catching other I/O errors. Which exception should be caught?

When a class defines both __getattr__ and __getattribute__, which one is called when accessing an attribute that exists in the instance?

A developer installs a third-party package using pip, but when they try to import it in their script, Python raises a ModuleNotFoundError. The package is definitely installed (pip list shows it). What is the most likely cause?

A class MyClass defines __str__ and __repr__ methods. What is the purpose of __repr__?

A developer runs 'pip install mypackage' but gets a 'PermissionError'. Which command should be used to install the package for the current user only?

Drag and drop the steps to debug a Python script using pdb into the correct order.

A developer wants to implement a read-only property for a class 'Temperature' that returns the temperature in Celsius but prevents external modification. Which code snippet correctly defines such a property?

A team is developing a system that must handle different types of documents (PDF, Word, etc.). Each document type has a unique parsing method. To avoid massive conditional logic, which OOP concept should be applied?

Refer to the exhibit. Which of the following correctly shows the MRO of class D?

A user entered a string ' Hello, World! '. Which expression returns 'Hello, World!'?

Which TWO statements about Python's name mangling are correct?

Which THREE methods return a boolean value?

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?

A developer wants to ensure that a file is always closed after writing, even if an exception occurs. Which approach is considered best practice in Python?

A developer is working on a logging system where dynamic values are inserted into a template string. The template is 'User %s logged in at %s'. The developer has the username and timestamp as separate variables. Which approach is most Pythonic (PEP 498) and recommended for new code?

A Python class 'Shape' defines an abstract method 'area'. Subclasses 'Circle' and 'Square' implement 'area'. A function 'calculate_area(shape)' expects a 'Shape' instance. Which principle ensures that the function works correctly without knowing the specific subclass?

A developer defines a class with a private attribute `_value` and wants to provide controlled access. Which approach is the most Pythonic?

Which THREE of the following are characteristics of Python's special methods (dunder methods)? (Select exactly three.)

A developer writes a class `Logger` with a method `log(self, message)`. They want to ensure that when `Logger` is subclassed, any override of `log` must call the parent's `log` method. Which technique best enforces this requirement in Python?

When processing a large text file, a developer notices that using str.replace() in a loop is slow. Which alternative is most efficient for multiple replacements?

A developer writes: s = 'abc'; s[0] = 'x'. What happens?

Drag and drop the steps to create a simple HTTP server using the http.server module in Python into the correct order.

Which THREE of the following are valid ways to create a string in Python?

Which of the following expressions returns the string 'Hello' repeated three times?

Which mode should be used when opening a file for writing such that new content is appended to the end without truncating existing content?

Which expression returns the last character of string s?

Match each list method to its effect.

Which THREE of the following escape sequences are valid in a Python string and represent a single character? (Select exactly three.)

Which string method would you use to check if a string starts with a specified prefix?

Consider the following class hierarchy: class A: def method(self): return 'A'; class B(A): pass; class C(A): def method(self): return 'C'; class D(B, C): pass. What is the output of D().method() according to Python's MRO?

Refer to the exhibit. Which of the following is the most likely cause of this error?

A developer writes a script that reads a configuration file. If the file does not exist, the program should print an error and continue. Which code snippet correctly implements this behavior?

Refer to the exhibit. What does the 'from None' clause do in the second raise statement?

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'?

Which of the following exception classes is NOT a direct subclass of Exception in Python?

Refer to the exhibit. If the file config.cfg exists but the user does not have read permission, what will be printed?

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

What is the result of the expression '123'.zfill(5)?

A developer is building an IoT application that reads temperature data from a sensor over a TCP socket. The sensor sends data as a stream of bytes encoded in UTF-8, with each reading terminated by a newline character. The developer uses the following code to receive data: ```python import socket s = socket.socket() s.connect(('sensor.local', 5000)) data = s.recv(1024) ``` The variable `data` is a bytes object. The developer needs to convert it to a string to parse the temperature value. Which of the following lines of code should the developer use to correctly obtain the string representation of the received data, assuming the data is valid UTF-8 and may contain non-ASCII characters?

Which TWO of the following are appropriate techniques for logging exception details in Python? (Select exactly 2)

Consider the following code snippet: 'class A: pass; class B(A): pass; class C(A): pass; class D(B, C): pass'. What is the Method Resolution Order (MRO) for class D according to the C3 linearization algorithm used by Python?

Refer to the exhibit. What is the output of the code?

What will the above code output?

Given the code above, what is printed? Note: each backslash is a single character.

A class has a class attribute that is a list. A developer modifies this list via one instance, and the change is reflected in all other instances. What is the best practice to avoid this unintended sharing?

Refer to the exhibit. A developer ran the script and saw the above traceback. The intended behavior was to load a JSON configuration file, and if the file is missing, create a default config. What is the most likely root cause of the second exception (NameError)?

A developer is validating user input in a Python application. The string variable `input_str` is assigned the value `'Hello World'`. Which TWO of the following conditions evaluate to `True`? (Choose two.)

Consider the following code snippet: s = 'abcdefgh'; result = s[7:3:-2]; print(result). What is the output?

A web application receives a byte string b'\xc3\xa9' which represents the character 'é' in UTF-8. The developer wants to convert it to a Python string. Which operation should be used?

You are developing a Python application that processes financial transactions. The application is structured as a package named `finance`. Inside `finance`, there are subpackages: `models`, `services`, and `utils`. The `services` subpackage contains a module `validator.py` that defines a function `validate_transaction()`. This function uses a helper function `check_amount()` defined in `utils.helpers`. The package is used by multiple other projects, and you want to ensure that importing `finance` does not accidentally expose internal helper functions. You also want to allow users to easily import the main validation function via `from finance import validate_transaction`. Which of the following approaches best achieves these goals?

Which THREE of the following string methods can be used to split a string into a list of substrings? (Choose three.)

A programmer wants to create a package named 'analytics' with subpackages 'statistics' and 'ml'. Which directory structure correctly defines these packages?

A developer writes: print('{:,}'.format(1234567)). What is the output?

Refer to the exhibit. What is the output of the last line?

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

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?

Which TWO of the following are valid string methods in Python?

Refer to the exhibit. What happens when the last line is executed?

A developer is writing a package that contains multiple modules. The package should allow users to import it directly and have all commonly used functions available at the package level. For example, after `import mypackage`, the user should be able to call `mypackage.func1()` without needing to import submodules. Which is the best way to achieve this?

Which THREE of the following statements about Python packages and modules are true?

Refer to the exhibit. The above log shows an unhandled exception that caused the program to crash. The developer wants to handle this exception and log the error without crashing. Which exception type should be caught in the main code to capture this specific error?

Refer to the exhibit. A Python script uses the following code to load the policy. However, it fails with a JSONDecodeError. What is the most likely cause? ```python import json with open('policy.json', 'r') as f: policy = json.load(f) ```

A Python class 'BankAccount' has a method 'withdraw(amount)' that deducts 'amount' from 'self.balance'. A developer writes a subclass 'SavingsAccount' that overrides 'withdraw' to add a penalty if balance drops below minimum. Which design pattern is being used?

A Python project uses namespace packages spread across multiple directories. The package structure is: project/ and lib/ both contain subdirectories 'mypkg/'. Each has an __init__.py file. When importing 'mypkg', which directory's contents are used?

A developer needs to extract the file extension from a filename like 'document.pdf'. Which expression returns 'pdf'?

What is the result of the expression '12345'[:10]?

A Python application processes user-uploaded files. The requirement is to catch any I/O-related exception while reading the file, but not to catch KeyboardInterrupt or SystemExit. Which exception type should be caught?

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?

Which of the following best describes the use of the @abstractmethod decorator in Python?

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?

A company needs to model different types of employees. They have a base class `Employee` with a method `calculate_pay()`. For hourly employees, pay = hours * rate; for salaried employees, pay = salary. Which design approach is most appropriate?

A class 'Point' is defined with __slots__ = ['x', 'y']. A developer creates an instance p = Point() and tries to set p.z = 10. What happens?

Refer to the exhibit. If /var/data/in.csv does not exist, what exception is raised?

Given the string 'Python', what is the result of 'Python'[::-1]?

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?

A developer defines a class 'Car' with an attribute 'wheels = 4'. They create two instances: car1 = Car() and car2 = Car(). Then they set car1.wheels = 3. What is the value of car2.wheels?

A junior developer wrote a class representing a bank account with a private attribute balance. They used double underscore prefix (__balance) to make it private. However, in a test script, they are still able to access the attribute using the mangled name _Account__balance. The developer is confused about why encapsulation is not enforced. Which statement best explains this behavior?

Consider the following code: class A: x = 1; class B(A): pass; class C(A): x = 2; class D(B, C): pass. What is D.x?

Which TWO of the following expressions evaluate to `True`? (Select exactly two.)

Which string method can be used to check if a string contains only digits?

Consider the following code: result = ' '.join(['a', 'b', 'c']) print(repr(result)) What is the output?

Refer to the exhibit. A Python script uses re.split with a regex pattern. What is the output?

A developer has two separate directories on sys.path: /home/user/libs and /opt/libs. Both directories contain a subdirectory 'mypackage' without an __init__.py file. The developer wants to import a module from 'mypackage' that exists only in one of the directories. What concept allows Python to treat these two directories as a single namespace package?

A data scientist needs to count the occurrences of a substring in a long DNA sequence (e.g., 1 million bases). However, the count must include overlapping occurrences. For example, in 'AAAA', the substring 'AA' appears three times overlapping. The built-in count() method does not count overlapping matches. The scientist needs a function to count overlapping substrings efficiently without using third-party libraries. Which of the following approaches is the most efficient for this task?

Consider the following code: print('"age": 30,')

Which TWO of the following string methods return a new string without modifying the original?

Which TWO of the following are valid ways to read a file line by line without loading the entire file into memory?

What is the output of the following code? s = 'Hello'; print(s.find('l'))

Refer to the exhibit. What is the root cause of the error?

You maintain a Python library 'myutils' that is installed as a package in the system. The library has a submodule 'config' that reads configuration from a file. Recently, a user reported that after updating the library, their application still uses the old configuration values. They confirmed that the config file on disk has been updated. The library's __init__.py does: from .config import load_config. The user's application imports load_config from myutils and calls it each time they need configuration. What is the most likely cause of the issue?

A programmer wants to create a class that cannot be instantiated directly, only through a factory method. Which approach should be used?

Which THREE of the following expressions return the string "Python"? (Choose three.)

Which TWO of the following are immutable in Python?

Consider the following code snippet: try: x = int(input()) y = 10 / x print(y) except ZeroDivisionError: print('Division by zero') except ValueError: print('Invalid integer') If the user enters '0', what is the output?

A module 'shapes.py' defines several classes: Circle, Square, Triangle. The developer wants to allow users to import only Circle and Square when they use 'from shapes import *'. Which mechanism should be used?

A class `ServerConfig` has a class attribute `port = 8080`. After deployment, a developer runs `ServerConfig.port = 9090` in one module, and unexpectedly all existing instances now use port 9090. What concept explains this behavior?

A class has a method that does not access any instance or class data. What decorator should be used to define it as a utility method that can be called on the class itself without requiring an instance?

What will be the output of the following code? try: print(1/0) except: print('error') else: print('no error') finally: print('done')

Which TWO of the following string methods modify the string in place? (Note: Python strings are immutable.)

Which of the following is the correct way to open a file for writing in text mode, ensuring that if the file already exists it will be overwritten?

A developer needs to write binary data to a file. Which file mode should be used to open the file for writing in binary mode without truncating it if it already exists?

A developer is troubleshooting an ImportError: 'No module named 'config''. The config module is located in a subdirectory 'utils' relative to the script. The script's current working directory is the parent of 'utils'. Which of the following lines, added to the script, will resolve the issue?

Which THREE are valid escape sequences in Python strings?

Which TWO statements about method overriding in Python are correct?

Which THREE of the following are valid string methods in Python? (Choose three.)

What is the result of the expression 'Hello'[1:3]?

What is the output of the following code? try: raise ValueError('a') except ValueError as e: print(e.args[0]) finally: print('b')

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?

A developer wants to ensure that the 'radius' attribute of a Circle class is always non-negative. Which implementation using @property is correct?

A Python developer is implementing a class that should behave like a sequence and support indexing. Which pair of special methods must be defined to achieve this?

A class named Counter has a class variable count and an instance method increment. The method is defined as def increment(self): Counter.count += 1. What will be the output after executing the following code? c1 = Counter(); c2 = Counter(); c1.increment(); c2.increment(); print(Counter.count, c1.count, c2.count)

Which TWO of the following are built-in Python exceptions?

Which TWO statements about the __init__.py file in a Python package are true?

Which of the following expressions raises a ValueError?

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?

Refer to the exhibit. Which THREE statements about the class hierarchy are correct?

Which two of the following are valid ways to create a multiline string in Python source code? (Choose two.)

Match each variable scope to its description.

A developer is building a configuration parser. They have a string `line = " key = value "` and need to remove the leading and trailing spaces, then split the line at the equals sign into a list of exactly two elements: the key and the value, with any spaces around the equals sign removed. Which expression achieves this?

A developer wants to ensure that a file is always closed, even if an exception occurs, without using the 'with' statement. Which approach correctly achieves this?

Which TWO of the following operations can be performed on a string?

A developer writes a class `Circle` with `def __init__(self, radius): self.radius = radius` and wants printing a `Circle` instance to produce a readable description such as `Circle(5)`. Which method should be implemented, and why over the alternative?

A class inherits from two parent classes that both have a method with the same name. When calling the method on the child, only one parent's version is executed. What Python mechanism determines which one?

A developer is working on a data pipeline that processes files from untrusted sources. The pipeline should catch and log any exception, but also ensure that sensitive information from the exception (e.g., file paths) is not exposed to end users. Which approach balances security and debugging?

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

A developer wants to check if a string ends with a specific suffix. Which method should be used?

A programmer wants to catch both `FileNotFoundError` and `PermissionError` with a single except clause. Which tuple is correct?

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

A developer needs to format a floating-point number 123.456789 with exactly 2 decimal places and a width of 10 characters, right-aligned. Which format specifier accomplishes this?

Which TWO of the following are valid ways to define a class method in Python? (Select exactly two.)

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?

A developer writes a function to reverse a string: def reverse_str(s): return s[::-1]. Which of the following statements about this function is true?

Consider the following directory structure: project/ main.py pkg/ __init__.py mod1.py subpkg/ __init__.py mod2.py From main.py, you write: from pkg.subpkg import mod2 Which THREE of the following are true regarding relative imports?

Refer to the exhibit. What will happen when the code is executed?

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

A developer needs to extract the file extension from a string like 'report.pdf'. Which string method is most appropriate?

A small web application allows users to download files from a server. The code uses open() without any exception handling. When a user requests a non-existent file, the server crashes with a traceback and returns a 500 Internal Server Error to the client. The team needs to modify the code to handle this situation gracefully: if the file does not exist, the application should return a 404 Not Found response (by calling a function send_404()). The application should not catch unrelated exceptions like KeyboardInterrupt. Which modification is the most appropriate?

A class has an attribute that should be computed on access and cached for subsequent accesses. Which pattern is most appropriate?

Which THREE of the following are valid escape sequences in Python strings?

A pipeline processes many small binary records. The developer writes a custom exception `class RecordError(Exception)` with an `__init__` that stores a record identifier and calls `super().__init__(message)`. A validation function raises `RecordError` for a corrupt record, and a worker catches it to log the identifier. The worker also wants the raw message to be available via `str(e)`. Which statement about this design is correct?

In a performance-critical application, you need to concatenate many strings in a loop. Which TWO approaches are most efficient?

A developer defines a class hierarchy with multiple inheritance: class A, class B(A), class C(A), class D(B,C). The method 'm' is defined only in A. What is the method resolution order for D according to the C3 linearization algorithm?

Which TWO of the following are valid ways to define a class attribute that is shared among all instances?

A developer is implementing a custom exception for invalid data. Which class should the custom exception inherit from?

A developer writes a function that reads a configuration file and returns its contents as a string. The file might not exist. Which exception should be caught to handle a missing file?

A team is developing a large Python application with multiple modules. They encounter an ImportError when module A tries to import from module B, and module B tries to import from module A. What is the most likely cause and best practice to resolve this?

Under CPython, what is the result of the following code? a = 'hello'; b = 'hello'; print(a is b)

A developer creates a metaclass 'Meta' that modifies class creation by adding a class attribute 'created_by' set to 'Meta'. Which code snippet correctly defines and uses this metaclass?

Which of the following best describes the immutability of strings in Python?

Which two methods can be used to remove leading whitespace from a string? (Choose two.)

A developer wants to ensure that a class attribute is shared across all instances. Which approach should be used?

A programmer writes a function that expects a string and returns it reversed. Which code snippet correctly reverses the string 'stressed' to 'desserts'?

Which of the following is true regarding Python's method resolution order (MRO) in multiple inheritance?

Which TWO of the following are valid ways to use string formatting in Python? (Choose two.)

A team is using inheritance but wants to prevent a method from being overridden in subclasses. What Python feature can enforce this?

Which TWO of the following are correct ways to raise a custom exception in Python? (Assume CustomError and CustomException are user-defined.)

A data scientist writes a script to parse a configuration file that contains lines in 'key=value' format. Some lines may have malformed data that cause a ValueError when trying to convert the value to an integer. The requirement is to process all valid lines and skip any that cause a ValueError, but continue processing subsequent lines. The script should log a warning for each skipped line, including the line number. Which implementation correctly fulfills this requirement? (Assume the file is opened with 'with open(...) as f'.)

Which THREE of the following are valid ways to import a function named 'calculate' from a module named 'math_ops' located in a subpackage 'operations' of a package 'app'?

Which of the following statements about the __init__.py file in a package is true?