Python Questions

Karan Bhardwaj

Score: 🔥 123

Intermediate

Took 2 months

Programming Language

Python

86%

Questions Attempted

15 / 15

Correct Answers

Incorrect Answers

Points Earned

🔥 13

Question 1

What is the output of the following code snippet?

matrix = [[1, 2, 3], [4, 5, 6]]
print(matrix[0][2])

1
2
3
IndexError: list index out of range

Explanation:

matrix[0] accesses the first sublist [1, 2, 3], and then [0][2] accesses the third element in that sublist, which is 3.

Question 2

What is the purpose of the finally block in Python exception handling?

It always executes after a try block, regardless of whether an exception occurred.
It executes only if an exception occurs in the try block.
It defines a custom exception to be raised.
It specifies the type of exception to catch.

Explanation:

The finally block is used for cleanup actions that should always happen, like closing files or releasing resources, whether an exception occurred or not.

Question 3

In a function definition, what is the order in which you should define different types of arguments?

keyword arguments, *args, positional arguments, **kwargs
*args, positional arguments, **kwargs, keyword arguments
positional arguments, keyword arguments, *args, **kwargs
**kwargs, keyword arguments, *args, positional arguments

Explanation:

This is the standard order enforced by Python to avoid ambiguity in function definitions and calls. Mixing the order can lead to syntax errors.

Question 4

What is the primary advantage of using the with statement for file operations in Python?

It automatically closes the file, even if exceptions occur.
It improves code readability.
It provides better performance for large files.
All of the above.

Explanation:

The with statement provides all these benefits: automatic file closure (ensuring resources are released), improved code readability, and slightly better performance in some cases.

Question 5

How can you access the constant 'pi' from the 'math' module after importing it?

math.pi
pi
math->pi
math(pi)

Explanation:

After importing a module, you use the dot notation (.) to access its members. Therefore, 'math.pi' correctly retrieves the value of 'pi' from the 'math' module.

Question 6

How can you best describe the functionality of a decorator in Python?

It modifies the behavior of a function without directly altering its source code.
It enforces type checking on function arguments.
It defines a new class dynamically.
It creates a copy of a function with a different name.

Explanation:

Decorators provide a clean way to extend or modify the functionality of existing functions by wrapping them in another function. This is a key aspect of aspect-oriented programming in Python.

Question 7

What is the purpose of the 'r' prefix in a regular expression pattern?

It makes the pattern case-insensitive.
It treats the pattern as a raw string, ignoring escape sequences.
It enables multiline matching.
It performs a greedy match.

Explanation:

The 'r' prefix before a regular expression pattern in Python indicates a raw string literal, which treats backslashes as literal characters, avoiding the need to escape them.

Question 8

In Python, what is the difference between a class variable and an instance variable?

Class variables are declared inside a method, while instance variables are declared outside methods.
Class variables are shared by all instances of a class, while instance variables are unique to each instance.
Class variables can only store integers, while instance variables can store any data type.
There is no difference; they are interchangeable terms.

Explanation:

Class variables hold data associated with the class itself, and this data is shared across all instances. Instance variables, on the other hand, store data that is specific to each individual object (instance) created from the class.

Question 9

What does the following code snippet print?

def outer_func(x):
    def inner_func(y):
        return x + y
    return inner_func

my_func = outer_func(5)
print(my_func(3))

8
15
5
Error

Explanation:

This demonstrates closures. inner_func has access to x from outer_func even after outer_func has finished executing. When my_func(3) is called, it adds 3 to the remembered x value of 5.

Question 10

What is a key characteristic of a closure in Python?

It allows a function to be defined inside a class.
It prevents a function from accessing global variables.
It allows a nested function to 'remember' and access variables from its enclosing function's scope even after the outer function has finished executing.
It forces a function to return a value of a specific data type.

Explanation:

Closures are important for creating functions that maintain state between calls, even without using global variables, making code more modular and organized.

Question 11

What is the output of the following Python code:

string = 'Hello, world!'
print(string.replace('o', '0', 1))

Hell0, world!
Hell0, w0rld!
Hello, world!
Error

Explanation:

The replace() method replaces the first occurrence of the specified substring ('o') with the new substring ('0') because the optional third argument (count) is set to 1.

Question 12

In Python, how do you access an instance variable within a class method?

Using the class name followed by the variable name.
Using the 'self' keyword followed by the variable name.
Directly using the variable name.
Instance variables cannot be accessed within class methods.

Explanation:

'self' represents the instance of the class. Inside a class method, 'self.variable_name' is used to access or modify the instance variable associated with that specific instance.

Question 13

What is the most efficient way to concatenate a large number of strings in Python?

Using the '+' operator.
Using the ''.join() method.
Using the '%s' operator.
It depends on the size of the strings.

Explanation:

The ''.join() method is the most efficient way to concatenate a large number of strings in Python because it avoids creating intermediate string objects, unlike the '+' operator.

Question 14

What is the primary purpose of decorators in Python?

To change the behavior of a function without modifying its source code.
To define a function within another function.
To create recursive functions.
To improve the performance of a function.

Explanation:

Decorators allow you to wrap a function with another function, modifying its behavior without directly altering its implementation.

Question 15

What is the purpose of using a default argument in a Python function?

To make the function return a default value if no arguments are provided.
To specify a value for an argument if it is not passed in the function call.
To define a variable that can only be accessed within the function.
To create a function that can accept any number of arguments.

Explanation:

Default arguments allow you to set a predefined value for a parameter, which will be used if the caller doesn't provide a value for that parameter.