Hackerrank Python Data Structures & Algorithms 2

Question 1

What is the purpose of the `__init__` method in a Python class?

Accepted Answer

To initialize the attributes of a new object when it is created

Answer

The __init__ method is the constructor that runs automatically when a new instance of a class is created, allowing you to set initial values for the object's attributes.

Question 2

What does the `lambda` keyword create in Python?

Accepted Answer

An anonymous (unnamed) function defined in a single expression

Answer

Lambda creates a small anonymous function that can take any number of arguments but can only contain a single expression. It is often used with functions like map(), filter(), and sorted().

Question 3

What is the output of: print(type({}))?

Accepted Answer

Answer

Empty curly braces {} create an empty dictionary in Python, not an empty set. To create an empty set, you must use set(). This is a common Python gotcha.

Question 4

Which method would you use to remove and return the last element from a Python list?

Accepted Answer

pop()

Answer

The pop() method without arguments removes and returns the last element of a list. With an index argument, it removes and returns the element at that position.

Question 5

What is a Python generator and how does it differ from a regular function?

Accepted Answer

A function that uses yield to produce a sequence of values lazily, one at a time

Answer

Generators use the yield keyword to produce values one at a time on demand (lazy evaluation), saving memory compared to creating an entire list. They maintain state between yields.

(Hackerrank) HackerRank Python Certification Practice Test

(Hackerrank) HackerRank Python Certification Practice Test

Hackerrank Python Data Structures & Algorithms 2