Untitled Deck

Question 1

What is the difference between a module and a package in Python?

Answer 1

• Module: a single .py file containing functions, variables, or classes
• Package: a directory with an __init__.py file and multiple modules inside

Packages help organize code logically and make it reusable and easier to manage.

Question 2

What does the import statement do in Python?

Answer 2

It allows you to reuse code from other files or libraries

This promotes the use of existing solutions and helps build modular, scalable programs.

Question 3

What is the purpose of the __init__.py file in a package?

Answer 3

It initializes a package and/or its sub-packages

The file may be empty but must not be absent for the directory to be recognized as a package.

Question 4

What does the dir() function do?

Answer 4

Shows a list of the entities contained inside an imported module

Example: dir(os) will list all attributes, functions, and classes defined in the os module.

Question 5

What is the role of the sys.path variable?

Answer 5

Controls where Python looks for modules when using an import statement

It determines the search path Python follows to locate the files that define the modules you’re importing.

Question 6

List the functions provided by the math module.

Answer 6

• ceil()
• floor()
• trunc()
• factorial()
• hypot()
• sqrt()

These functions perform various mathematical operations.

Question 7

What does the math.ceil(x) function do?

Answer 7

Rounds up to the nearest integer (toward +∞)

Example: math.ceil(3.1) returns 4.

Question 8

What does the random.random() function return?

Answer 8

A random float in the range (0.0, 1.0)

Example output: 0.5738…

Question 9

What is the purpose of the random.seed(x) function?

Answer 9

Initializes the random number generator for reproducibility

Always use seed() before random() if you want repeatable output.

Question 10

What does the platform.platform() function return?

Answer 10

A single string describing the full platform

Example output: ‘Windows-10-10.0.19041-SP0’.

Question 11

What is the significance of the __name__ variable in Python?

Answer 11

Indicates if a file is run directly or imported as a module

If run directly, __name__ is set to __main__; if imported, it is set to the file’s name.

Question 12

True or false: The finally branch of the try statement is executed only if an exception occurs.

Answer 12

FALSE

The finally branch is always executed, regardless of whether an exception occurred.

Question 13

What are abstract expressions in the context of Python exceptions?

Answer 13

Base classes in the exception hierarchy not meant to be raised directly

They provide categorization or grouping of related errors.

Question 14

List three examples of concrete built-in Python exceptions.

Answer 14

• AssertionError
• ImportError
• IndexError

These represent actual error conditions that can occur.

Question 15

What does the except (e1, e2) syntax do?

Answer 15

Catches multiple types of exceptions in one block

e1 and e2 must be exception types like ValueError or TypeError.

Question 16

What is the purpose of the __pycache__ directory?

Answer 16

Stores semi-compiled .pyc files for imported modules

This improves performance by avoiding recompilation on subsequent imports.

Question 17

What is a namespace in Python?

Answer 17

A mapping between names and objects (like variables or functions)

Different types include local, global, nonlocal, and built-in namespaces.

Question 18

Fill in the blank: A module is designed to couple together some related entities such as functions, variables, and _______.

Answer 18

constants

This helps in organizing code logically.

Question 19

Name some concrete built-in Python exceptions.

Answer 19

• AssertionError
• ImportError
• IndexError
• KeyboardInterrupt
• KeyError
• MemoryError
• OverflowError

These exceptions are part of Python’s built-in exception hierarchy.

Question 20

What is the purpose of the raise statement in Python?

Answer 20

• Raise an exception on demand
• Re-raises the current exception
• Raises the exception stored in a variable

The raise statement can be used to trigger exceptions intentionally.

Question 21

True or false: Assertions are used for handling runtime errors.

Answer 21

FALSE

Assertions are primarily used for debugging and can be disabled when Python is run with the -O flag.

Question 22

What are event classes in Python exceptions?

Answer 22

• Represent errors and signals
• Can be caught, raised, and defined
• Allow precise error handling and flow control

Event classes include exceptions like KeyboardInterrupt and SystemExit.

Question 23

What does the syntax except E as e: do?

Answer 23

Catches a specific exception and assigns it a name

This allows you to access the details of the exception after catching it.

Question 24

What is the args property in Python exceptions?

Answer 24

A tuple containing the arguments passed to the exception

You can access individual arguments using ex.args[index].

Question 25

How can you create a **custom exception** in Python?

Answer 25

Define a class that inherits from `Exception` ## Footnote You can add custom properties and methods to manage the exception's behavior.

Question 26

What are the **encoding standards** mentioned for character representation?

Answer 26

* ASCII * UNICODE * UTF-8 ## Footnote These standards are commonly used in IT for encoding characters.

Question 27

What is a **code point**?

Answer 27

A number corresponding to a particular character ## Footnote For example, *32* is the code point for a space in ASCII encoding.

Question 28

What does **BOM** stand for in encoding?

Answer 28

Byte Order Mark ## Footnote It indicates the encoding used by a file's contents.

Question 29

True or false: **Python strings** can be changed in-place.

Answer 29

FALSE ## Footnote Strings in Python are immutable, meaning they cannot be modified after creation.

Question 30

What does the **ord()** function do?

Answer 30

Returns the ASCII/UNICODE code point value of a character ## Footnote For example, `ord('a')` returns 97.

Question 31

What does the **chr()** function do?

Answer 31

Returns the character corresponding to a given code point ## Footnote For example, `chr(97)` returns 'a'.

Question 32

What is the difference between **sort()** and **sorted()**?

Answer 32

* `sort()`: Sorts a list in place * `sorted()`: Returns a new sorted list ## Footnote `sort()` modifies the original list, while `sorted()` does not.

Question 33

What does the method **.isalpha()** check?

Answer 33

Checks if the string consists only of letters ## Footnote Returns `True` if the string contains only alphabetic characters.

Question 34

What does the method **.split(sep)** do?

Answer 34

Splits a string into a list using a separator ## Footnote For example, `'a-b-c'.split('-')` returns `['a', 'b', 'c']`.

Question 35

What is the purpose of **encapsulation** in Object-Oriented Programming?

Answer 35

Hides the internal state of an object and requires all interaction to be performed through an object's methods ## Footnote This promotes modularity and protects object integrity.

Question 36

What is a **subclass**?

Answer 36

A class that is derived from another class ## Footnote The class from which it is derived is called the superclass.

Question 37

What is the role of a **superclass**?

Answer 37

The class from which subclasses are derived ## Footnote It can provide common properties and methods to its subclasses.

Question 38

What is the significance of **two underscores (`__`)** at the start of a class component's name?

Answer 38

Indicates that the component is private ## Footnote This is part of Python's name mangling feature to prevent name clashes.

Question 39

What is an **inheritance diagram**?

Answer 39

A diagram where superclasses are presented above their subclasses and relations are shown as arrows directed from the subclass toward its superclass ## Footnote It visually represents the hierarchical structure of classes.

Question 40

What are the components of an object?

Answer 40

* Name * Properties * Methods ## Footnote Objects can have a set of properties and methods, which can be empty.

Question 41

What happens if a class component has a name starting with two underscores (`__`)?

Answer 41

It becomes **private** and can only be accessed from within the class ## Footnote This is how Python implements the **encapsulation** concept.

Question 42

What is a **constructor** in Python?

Answer 42

A method named `__init__` responsible for creating new objects ## Footnote It cannot return any value and cannot be invoked directly.

Question 43

True or false: An **instance variable** exists independently of an object.

Answer 43

FALSE ## Footnote Instance variables depend on the creation of an object.

Question 44

What is the purpose of the `__dict__` property?

Answer 44

It stores all instance variables in a dedicated dictionary for each object ## Footnote Class variables are not shown in an object's `__dict__`.

Question 45

List the features of **private attributes** in instances vs. classes.

Answer 45

* Defined in `__init__()` or methods (instance) * Defined directly inside class body (class) * Uses `self` (instance) * Does not use `self` (class) ## Footnote Private attributes are accessed differently in instances and classes.

Question 46

What is the **self** parameter used for in methods?

Answer 46

To obtain access to the object's instance and class variables ## Footnote It is always the first parameter in a method.

Question 47

What does the `hasattr()` function do?

Answer 47

Checks if an object/class contains a specified property ## Footnote It returns True or False.

Question 48

What does the `issubclass(Class_1, Class_2)` function determine?

Answer 48

If `Class_1` is a **subclass** of `Class_2` ## Footnote It helps in understanding class hierarchies.

Question 49

What is **polymorphism** in Python?

Answer 49

The ability of a subclass to modify its superclass behavior ## Footnote It allows methods to behave differently based on the object.

Question 50

What does the `is` operator check?

Answer 50

If two variables refer to **the same object** ## Footnote It helps in understanding object identity.

Question 51

What is the purpose of the `__str__()` method?

Answer 51

To convert an object's contents into a readable string ## Footnote It can be overridden for custom string representation.

Question 52

What is **multiple inheritance**?

Answer 52

A class inherits from two or more classes ## Footnote It can lead to complexity and ambiguity in the inheritance hierarchy.

Question 53

What is the difference between **inheritance** and **composition**?

Answer 53

* Inheritance extends a class's capabilities * Composition projects a class as a container for other objects ## Footnote Both are ways to build class relationships.

Question 54

What does the `super()` function do?

Answer 54

Returns a reference to the nearest **superclass** of the class ## Footnote It is useful for accessing inherited methods.

Question 55

What is the **yield** statement used for?

Answer 55

To suspend function execution and return a value as part of a **generator** ## Footnote It can only be used inside functions.

Question 56

What is a **class variable**?

Answer 56

A property that exists in exactly one copy and doesn't need an object to be accessible ## Footnote Class variables are stored in a class's `__dict__`.

Question 57

The **yield** statement can be used only inside _______.

Answer 57

functions ## Footnote The yield statement suspends function execution and causes the function to return the yield's argument as a result.

Question 58

A **lambda** function is a function without a _______.

Answer 58

name ## Footnote Lambda functions are also called anonymous functions.

Question 59

The **map()** function applies a function to each element in an _______.

Answer 59

iterable ## Footnote It can be used with lists or tuples.

Question 60

The **filter()** function returns a new iterable containing only the elements for which the function returns _______.

Answer 60

True ## Footnote The filter function is useful for extracting elements that meet certain criteria.

Question 61

A **closure** allows the storing of values even when the context in which they were created _______.

Answer 61

does not exist anymore ## Footnote Closures are useful for maintaining state in nested functions.

Question 62

In Python, there are three **predefined streams**: _______.

Answer 62

* sys.stdin * sys.stdout * sys.stderr ## Footnote These streams are automatically available for input, output, and error handling.

Question 63

The **open()** function syntax is used to open a file: open(file_name, mode=open_mode, _______).

Answer 63

encoding=text_encoding ## Footnote This function creates a stream object associated with the specified file.

Question 64

The **errno** variable contains a property named _______ when any file operation fails.

Answer 64

errno ## Footnote This property helps diagnose the problem with file operations.

Question 65

To read a file’s contents, the following stream methods can be used: _______.

Answer 65

* read(number) * readline() * readlines(number) ## Footnote These methods allow for different ways to read data from a file.

Question 66

A **bytearray** is a mutable sequence of _______.

Answer 66

bytes ## Footnote It is useful for buffering binary input/output.

Question 67

In text mode, data type is _______ and requires encoding.

Answer 67

str ## Footnote Text mode is used for files that contain readable text.

Question 68

In binary mode, data type is _______ and does not require encoding.

Answer 68

bytes ## Footnote Binary mode is used for files that contain raw data.

Question 69

The **close()** method is used to _______ a file stream.

Answer 69

close ## Footnote It is important to close file streams to free up system resources.

Question 70

The **read()** method reads the specified number of _______ from the file.

Answer 70

characters/bytes ## Footnote It can read the whole file at once if no number is specified.

Question 71

The **write()** method writes a _______ to a text file.

Answer 71

string ## Footnote This method is used to add new content to a file.

Question 72

The **chunk size** in the context of reading data from a file can be set to _______.

Answer 72

1024 ## Footnote This is a common size for reading data in chunks.