Rakuten Associate Software Engineer Interview Questions and Answers

Python is a versatile language with easy syntax, vast libraries, and cross-platform compatibility.

• Python has a simple and readable syntax, making it easy to learn and write code quickly.

• Python has a vast collection of libraries and frameworks for various purposes, such as web development, data analysis, and machine learning.

• Python is cross-platform compatible, meaning that code written on one platform can run on anothe...read more

Python has several built-in datatypes including int, float, bool, str, list, tuple, set, and dict.

• int: used for integers, e.g. 5, -10

• float: used for floating-point numbers, e.g. 3.14, -2.5

• bool: used for boolean values, True or False

• str: used for strings, e.g. 'hello', 'world'

• list: used for ordered collections of items, e.g. [1, 2, 3]

• tuple: used for ordered collections of items that cannot be changed, e.g. (1, 2, 3)

• set:...read more

Lists and arrays in Python are both used to store multiple values, but they have some key differences.

• Lists can store elements of different data types, while arrays can only store elements of the same data type.

• Lists are dynamic in size, meaning they can grow or shrink as needed, while arrays have a fixed size.

• Lists have built-in methods for manipulation and iteration, while arrays require the use of external libraries

Slicing a list means extracting a portion of the list. Syntax: list[start:end:step]

• Start index is inclusive, end index is exclusive

• If start is not specified, it defaults to 0

• If end is not specified, it defaults to the end of the list

• If step is not specified, it defaults to 1

• Negative indices count from the end of the list

Python literals are fixed values that are used to represent data in code.

• Literals can be of various types such as string, integer, float, boolean, etc.

• They are used to assign values to variables or as arguments in functions.

• Examples of literals include 'hello world' (string), 42 (integer), 3.14 (float), True (boolean), etc.

Python generators are functions that return an iterator object which can be iterated over to produce a sequence of values.

• Generators are defined using the 'yield' keyword instead of 'return'.

• They allow for lazy evaluation, generating values on-the-fly instead of all at once.

• Generators can be used to generate an infinite sequence of values.

• They are memory efficient as they do not store the entire sequence in memory.

• Exam...read more

Literals are fixed values while variables can hold different values during program execution.

• Literals are hardcoded values in code, like 'hello' or 42

• Variables are containers that can hold different values during program execution

• Variables can be assigned literals or other variables

• Variables can be used to store and manipulate data

• Literals cannot be changed during program execution

Modules in Python are files containing Python code that can be imported and used in other Python programs.

• Modules are used to organize and reuse code in Python.

• They allow for better code organization and maintainability.

• Modules can be imported using the 'import' statement.

• Python provides a wide range of built-in modules, such as 'math' and 'random'.

• Custom modules can also be created to encapsulate related functionality

Constructors in Python are special methods used to initialize objects. They are called automatically when an object is created.

• Constructors have the same name as the class they belong to.

• They are defined using the __init__() method.

• Constructors can take arguments to initialize instance variables.

• If a class does not have a constructor, Python provides a default constructor.

• Constructors can also be used to perform any ot

Yes, Python has a destructor called __del__()

• The __del__() method is called when an object is about to be destroyed

• It is used to perform cleanup operations before the object is destroyed

• The __del__() method is not guaranteed to be called in all cases

init() method is a constructor in Python that initializes an object when it is created.

• It is called automatically when an object is created.

• It takes self as the first parameter.

• It can be used to initialize instance variables.

• It can also take additional parameters.

• Example: def __init__(self, name, age): self.name = name; self.age = age

Split() & Join() are string methods used to split a string into an array and join an array into a string respectively.

• Split() method is used to split a string into an array of substrings based on a specified separator.

• Join() method is used to join the elements of an array into a string using a specified separator.

• Both methods are commonly used in data processing and manipulation tasks.

• Example: var str = 'apple,banana,o...read more

Python iterators are objects that allow iteration over a collection of elements.

• Iterators are used to access elements of a collection sequentially.

• They are implemented using the __iter__() and __next__() methods.

• The __iter__() method returns the iterator object and the __next__() method returns the next element in the collection.

• Iterators can be used with loops, comprehensions, and other iterable functions.

• Examples of ...read more

Python has four types of values: integers, floating-point numbers, strings, and booleans.

• Integers are whole numbers, positive or negative, such as 5 or -10.

• Floating-point numbers are decimal numbers, such as 3.14 or -2.5.

• Strings are sequences of characters, enclosed in single or double quotes, such as 'hello' or "world".

• Booleans are either True or False, used for logical operations.

Python uses a dynamic memory allocation technique called reference counting.

• Python uses a heap data structure to store objects.

• Objects are created dynamically and stored in memory.

• Python uses a garbage collector to free up memory that is no longer being used.

• Python also uses a technique called memory pooling to reuse memory for small objects.

• Python supports both mutable and immutable objects, which affects how memory i

To delete a file in Python module, use the os module's remove() method.

• Import the os module

• Use the remove() method to delete the file

• Specify the file path in the remove() method

Global and local variables are used in Python to store values. Global variables can be accessed from anywhere in the code, while local variables are only accessible within a specific function.

• Global variables are declared outside of any function and can be accessed from anywhere in the code

• Local variables are declared within a function and can only be accessed within that function

• Global variables can be modified from w...read more

Flask and Django are popular python frameworks for web development.

• Flask is a micro web framework that is easy to learn and use.

• Django is a full-stack web framework that provides many built-in features.

• Other frameworks include Pyramid, Bottle, and Tornado.

• Flask and Django both use the WSGI standard for serving web applications.

• Flask is often used for small to medium-sized projects, while Django is better suited for lar...read more

Building blocks of OOP include encapsulation, inheritance, and polymorphism.

• Encapsulation: bundling data and methods that operate on that data within a single unit

• Inheritance: creating new classes from existing ones, inheriting their properties and methods

• Polymorphism: ability of objects to take on many forms, allowing for flexibility and extensibility

• Examples: class, object, method, constructor, interface, abstract cl

Pass by value and pass by reference are two ways of passing arguments to a function.

• Pass by value means that a copy of the argument is passed to the function.

• Pass by reference means that a reference to the argument is passed to the function.

• In pass by value, any changes made to the argument inside the function do not affect the original value.

• In pass by reference, any changes made to the argument inside the function af...read more

Function overloading is defining multiple functions with the same name but different parameters. Operator overloading is defining operators to work with user-defined types.

• Function overloading allows a function to perform different operations based on the number, type, and order of parameters.

• Operator overloading allows operators such as +, -, *, /, etc. to work with user-defined types.

• Function overloading is resolved ...read more

SQL is a programming language used to manage and manipulate relational databases.

• SQL stands for Structured Query Language.

• It is used to create, modify, and query databases.

• SQL is used in various industries such as finance, healthcare, and e-commerce.

• Examples of SQL-based databases include MySQL, Oracle, and Microsoft SQL Server.

Joins in SQL are used to combine data from two or more tables based on a related column.

• Inner join returns only the matching rows from both tables.

• Left join returns all the rows from the left table and matching rows from the right table.

• Right join returns all the rows from the right table and matching rows from the left table.

• Full outer join returns all the rows from both tables.

• Real world applications include combinin...read more

Indexes in SQL are used to improve query performance by allowing faster data retrieval.

• Indexes are data structures that provide quick access to data in a table.

• They are created on one or more columns of a table.

• Types of indexes include clustered, non-clustered, unique, and full-text indexes.

• Clustered indexes determine the physical order of data in a table, while non-clustered indexes are separate structures that point ...read more