PCAP Certified Associate in Python Programming Exam — Questions and Answers

Question 1: What is the precedence order (highest to lowest) for these operators: `+`, `**`, `*`?

*, **, +
+, *, **
**, *, + (Correct answer)
**, +, *

Correct answer: **, *, +

Python's operator precedence places `**` (exponentiation) highest, then `*` (multiplication), then `+` (addition).

Question 2: When iterating over a file object line by line with 'for line in file:', what is included in each line?

The line without any newline character
The line number followed by the text
The line with its trailing newline character (Correct answer)
Only the stripped whitespace-free content

Correct answer: The line with its trailing newline character

When iterating a file, each yielded string includes the trailing newline '\n', which you must strip manually if not needed.

Question 3: In Python, what does `del` define?

The logic for the `del` keyword on the class itself
A method to remove an item from a list attribute
A destructor called when the object is about to be garbage collected (Correct answer)
A method to delete a class attribute

Correct answer: A destructor called when the object is about to be garbage collected

`__del__` is the finalizer, invoked just before the interpreter destroys the object, though its exact timing is not guaranteed.

Question 4: Which built-in function is used to rename a file in Python?

file.rename()
shutil.rename()
os.move()
os.rename() (Correct answer)

Correct answer: os.rename()

os.rename(src, dst) renames the file or directory from src to dst.

Question 5: What is the value of `int(3.9)`?

4
3.9
3 (Correct answer)
ValueError

Correct answer: 3

`int()` truncates toward zero, so `int(3.9)` is `3`, not 4.

Question 6: In Python, which of the following is a mutable data type?

tuple
str
int
list (Correct answer)

Correct answer: list

Lists are mutable — their elements can be changed after creation; int, tuple, and str are immutable.

Question 7: What does os.walk() yield for each directory it visits?

A tuple of (dirpath, dirnames, filenames) (Correct answer)
A dict with 'root', 'dirs', and 'files' keys
A single Path object
A list of file paths only

Correct answer: A tuple of (dirpath, dirnames, filenames)

os.walk() yields a 3-tuple (dirpath, dirnames, filenames) for each directory in the tree rooted at the given path.

Question 8: Where does `pip install` place packages by default?

In a `packages/` folder next to the script
In the `site-packages` directory of the active Python environment (Correct answer)
In `/usr/local/lib/`
In the current working directory

Correct answer: In the `site-packages` directory of the active Python environment

`pip install` places packages in the `site-packages` directory of the currently active Python interpreter or virtual environment.

Question 9: In Python, what is a first-class function?

A function decorated with @classmethod
A function that can be passed as an argument, returned, or assigned to a variable (Correct answer)
A function defined at module level
A built-in function

Correct answer: A function that can be passed as an argument, returned, or assigned to a variable

First-class functions are treated like any other object — they can be stored in variables, passed to other functions, and returned from functions.

Question 10: What does `'hello'.upper()` return?

'hello'
'HELLO' (Correct answer)
'Hello'
None

Correct answer: 'HELLO'

upper() returns a new string with all characters converted to uppercase.

Question 11: What is the difference between a regular package and a namespace package?

A regular package can only be imported once; a namespace package can be reloaded
A regular package is a `.zip` archive; a namespace package is a directory
A namespace package is installed via pip; a regular package is local only
A regular package has `__init__.py`; a namespace package does not and can span multiple directories (Correct answer)

Correct answer: A regular package has `__init__.py`; a namespace package does not and can span multiple directories

Regular packages require `__init__.py`; namespace packages (PEP 420) lack it and allow merging directories across multiple locations into one logical package.

Question 12: How many times does this loop print? ``` for _ in range(3): for _ in range(2): print('x') ```

6 (Correct answer)
3
2
5

Correct answer: 6

The inner loop prints 2 times per outer iteration, and the outer runs 3 times: 3×2 = 6.

Question 13: Which of the following is a mutable data type in Python?

str
tuple
frozenset
list (Correct answer)

Correct answer: list

Lists are mutable — their elements can be changed after creation, unlike tuples, strings, and frozensets.

Question 14: How do you check if a string starts with a specific prefix in Python?

str.prefix('py')
str.begins('py')
str[:2] == 'py' only
str.startswith('py') (Correct answer)

Correct answer: str.startswith('py')

startswith() returns True if the string begins with the specified prefix.

Question 15: What is the effect of running Python with the `-O` (optimize) flag on `assert` statements?

They become no-ops that return True
They raise OptimizeWarning instead
They are completely removed and never execute (Correct answer)
They run faster

Correct answer: They are completely removed and never execute

With `-O`, Python strips all `assert` statements from the bytecode, so they never execute regardless of the condition.

Question 16: What does open(file, buffering=0) mean?

Use a 1-byte buffer
Use the default buffer size
Use an unlimited buffer
Disable buffering (only valid in binary mode) (Correct answer)

Correct answer: Disable buffering (only valid in binary mode)

Setting buffering=0 disables buffering; this is only permitted in binary mode and causes each read/write to go directly to the OS.

Question 17: What is the purpose of `PYTHONPATH` environment variable?

It specifies the location of the Python executable
It sets the default encoding for Python source files
It adds directories to `sys.path` at interpreter startup (Correct answer)
It controls which version of Python pip uses

Correct answer: It adds directories to `sys.path` at interpreter startup

Directories listed in `PYTHONPATH` (colon-separated on Unix) are prepended to `sys.path` when the interpreter starts.

Question 18: What is an 'editable install' (`pip install -e .`)?

An install that places the package in a temporary directory
An install that skips compiling `.pyc` bytecode files
An install where the package source directory is linked so code changes take effect immediately without reinstalling (Correct answer)
An install that allows editing the package's metadata after installation

Correct answer: An install where the package source directory is linked so code changes take effect immediately without reinstalling

Editable installs (development mode) add the source directory to `sys.path` via a `.pth` file so changes to the source are reflected instantly.

Question 19: Which of the following creates a set comprehension?

set(x*2 for x in range(5) using {})
{x*2 for x in range(5)} (Correct answer)
(x*2 for x in range(5))
[x*2 for x in range(5)]

Correct answer: {x*2 for x in range(5)}

Curly braces with a single expression and no colon create a set comprehension.

Question 20: What does `enumerate(['a','b','c'])` produce?

[0, 1, 2]
['a','b','c']
[(0,'a'),(1,'b'),(2,'c')] (Correct answer)
[('a',0),('b',1),('c',2)]

Correct answer: [(0,'a'),(1,'b'),(2,'c')]

enumerate() wraps an iterable and yields (index, value) tuples starting at 0 by default.

Question 21: What does `'hello world'.title()` return?

'Hello World' (Correct answer)
'HELLO WORLD'
'Hello world'
'hello world'

Correct answer: 'Hello World'

title() capitalizes the first letter of every word and lowercases the rest.

Question 22: What is the output of `len('hello world')`?

12
11 (Correct answer)
9
10

Correct answer: 11

The string 'hello world' has 5 + 1 space + 5 = 11 characters.

Question 23: What is the purpose of the errors parameter in open()?

Controls whether OSError is raised on write failure
Sets the maximum number of read errors allowed
Enables logging of I/O errors to stderr
Specifies how encoding/decoding errors are handled (Correct answer)

Correct answer: Specifies how encoding/decoding errors are handled

The errors parameter (e.g., 'ignore', 'replace', 'strict') defines what happens when a character cannot be encoded or decoded.

Question 24: A function is designed to process a dictionary. If a specific key is not found, the function should stop its normal execution and signal this specific problem to the caller. Which built-in exception is most appropriate to `raise` in this scenario?

AttributeError
KeyError (Correct answer)
ValueError
IndexError

Correct answer: KeyError

`KeyError` is the specific exception raised when a dictionary key is not found. `IndexError` relates to sequences like lists when an index is out of bounds. `ValueError` is for when an argument has the right type but an inappropriate value. `AttributeError` occurs when an attribute reference or assignment fails.

Question 25: Which symbol is used in Python's decorator syntax?

#
$
&
@ (Correct answer)

Correct answer: @

The @ symbol placed before a function definition applies the decorator to that function.

Question 26: What is the output of the following Python code snippet? ```python temperature = 25 if temperature > 30: print("Hot") elif temperature > 20: print("Warm") else: print("Cold") ```

No output will be generated.
Cold
Warm (Correct answer)
Hot

Correct answer: Warm

The code first checks if `temperature` (25) is greater than 30, which is false. It then proceeds to the `elif` condition, checking if 25 is greater than 20. This is true, so it prints "Warm" and exits the conditional block. The `else` block is never reached.

Question 27: Which module provides `contextmanager` decorator for creating context managers that handle exceptions?

functools
exceptions
contextlib (Correct answer)
builtins

Correct answer: contextlib

`contextlib.contextmanager` lets you write a generator-based context manager where code before `yield` is setup and code after `yield` (with try/except) handles teardown and exceptions.

Question 28: What does `pkgutil.iter_modules()` return?

A generator of module source code strings
A dict of module names to file paths
An iterator of `(finder, name, ispkg)` tuples for modules in given paths (Correct answer)
A list of all installed package names

Correct answer: An iterator of `(finder, name, ispkg)` tuples for modules in given paths

`pkgutil.iter_modules(path)` yields named tuples describing each module or subpackage found in the given list of directories.

Question 29: Which statement about Python indentation is correct?

Indentation is optional but recommended
Indentation must use exactly 4 spaces
Indentation defines code blocks and is syntactically required (Correct answer)
Indentation is only required inside classes

Correct answer: Indentation defines code blocks and is syntactically required

Python uses indentation to delimit code blocks; incorrect or inconsistent indentation causes an `IndentationError`.

Question 30: In a context manager using `exit`, what should the method return to suppress an exception?

True (Correct answer)
False
0
None

Correct answer: True

Returning `True` from `__exit__` tells Python to suppress the exception; any falsy return value lets the exception propagate.

Question 31: Which statement about `nonlocal` is correct?

It is only available in Python 2
It allows a nested function to assign to an enclosing (non-global) variable (Correct answer)
It allows access to global variables
It creates a new variable in the built-in scope

Correct answer: It allows a nested function to assign to an enclosing (non-global) variable

`nonlocal` lets an inner function rebind a variable in the nearest enclosing scope that is not the global scope.

Question 32: What does `'hello'.center(11, '*')` return?

'**hello***'
'***hello***' (Correct answer)
'*****hello'
'hello*****'

Correct answer: '***hello***'

center() pads the string to the specified total width by placing fill characters equally on both sides.

Question 33: Consider the following code. What will be the final output printed to the console? ```python def check_value(): try: print("Start") raise ValueError print("After Raise") except ValueError: print("Caught") return "From Except" finally: print("Cleanup") print("End") print(check_value()) ```

Start Caught Cleanup End From Except
Start After Raise End None
Start Caught Cleanup From Except (Correct answer)
Start Caught From Except Cleanup

Correct answer: Start Caught Cleanup From Except

The `try` block starts and prints "Start". A `ValueError` is immediately raised, so "After Raise" is skipped. The `except ValueError` block is executed, printing "Caught". It then prepares to return "From Except". However, the `finally` block must execute before the function officially returns, so "Cleanup" is printed. After the `finally` block completes, the function returns the value from the `except` block, which is then printed. "End" is never reached because the return statement exits the function.

Question 34: Which of the following is a positional-only parameter syntax introduced in Python 3.8?

def f(x, *, y):
def f(@x, y):
def f(x!, y):
def f(x, /, y): (Correct answer)

Correct answer: def f(x, /, y):

The `/` separator in a parameter list marks all parameters before it as positional-only — they cannot be passed by keyword.

Question 35: What is PYTHONCASEOK, and how does it work?

It is used to find the first case-insensitive match in a package statement
It is used to find the first case-sensitive match in an import statement
It is used to find the first case-insensitive match in an import statement (Correct answer)
None of these

Correct answer: It is used to find the first case-insensitive match in an import statement

PYTHONCASEOK is an environment variable that influences how Python handles module imports on case-insensitive file systems, like Windows. When set, Python will attempt to find a module even if its filename's casing doesn't exactly match the import statement. It allows for a case-insensitive search for the module file, importing the first match it finds.

Question 36: What is printed? val = '' if val: print('has value') elif val is None: print('is None') else: print('empty')

Error
has value
empty (Correct answer)
is None

Correct answer: empty

An empty string is falsy but not None, so neither the if nor the elif match, and 'empty' is printed.

Question 37: Which f-string expression correctly formats a float to 2 decimal places?

f'{value|2f}'
f'{value:.2f}' (Correct answer)
f'{value:2f}'
f'{value:.2}'

Correct answer: f'{value:.2f}'

The format spec :.2f means fixed-point notation with 2 digits after the decimal.

Question 38: Which attribute stores the exception that caused another exception when using implicit exception chaining?

__context__ (Correct answer)
__reason__
__cause__
__traceback__

Correct answer: __context__

`__context__` is set automatically when an exception is raised while another exception is already being handled (implicit chaining).

Question 39: Which method checks if all characters in a string are digits?

isdigit() (Correct answer)
isinteger()
isnumeric()
isnum()

Correct answer: isdigit()

isdigit() returns True if every character in the string is a decimal digit (0–9).

Question 40: What does `yield from` do in a generator function?

Creates a new generator function
Delegates to a sub-generator, yielding all its values (Correct answer)
Raises StopIteration immediately
Returns all values at once as a list

Correct answer: Delegates to a sub-generator, yielding all its values

yield from sub_gen delegates to a sub-generator, yielding each of its values as if they were in the outer generator.

Question 41: Which of the following is an invalid variable name in Python?

MYVAR
myVar2
2myVar (Correct answer)
_my_var

Correct answer: 2myVar

Python variable names must start with a letter (a-z, A-Z) or an underscore (_). They cannot begin with a digit. Therefore, '2myVar' is an invalid variable name. '_my_var', 'myVar2', and 'MYVAR' are all valid.

PCAP Certified Associate in Python Programming Exam

The PCAP certification validates intermediate Python skills including object-oriented programming, modules, exceptions, string processing, and advanced control flow.

Questions

65 min

Time Limit

70%

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