Top 100+ Python Interview Questions and Answers for 2023
Hey, this is Suraj. Today, Python is one of the most popular programming languages in the world now. We can use it for web development, artificial intelligence, data analysis, machine learning, scientific computing, and many more. Welcome to the Top 100+ Python Interview Questions and Answers for 2023, this is the platform to help you get the answers you need.
- What is Python and Why python is so famous?
Answer: Python is a high-level programming language and it is also a general-purpose programming language that was created by Guido van Rossum and released in 1991. It is known for its simplicity, readability, and flexibility, and is used in a wide variety of applications, such as web development, data analysis, scientific computing, artificial intelligence, and machine learning.
One of the reasons Python has become so popular is its ease of use and readability. The syntax of Python is straightforward and easy to understand, even for beginners. Additionally, Python has a vast library of modules and tools, which allows developers to build applications quickly and efficiently
- What are some features of Python?
Answer: Some of its key features include:
- Easy-to-learn syntax: Python’s syntax is designed to be intuitive and easy to learn, making it a popular choice for beginners and experienced programmers alike.
- Dynamic typing: Python is dynamically typed, meaning that variable types are determined at runtime rather than being explicitly declared.
- Interpreted: Python code is executed directly by an interpreter, without the need for compilation.
- Multi-paradigm: Python allows multiple programming paradigms so it may be procedural programming also object-oriented and functional programming.
- Large standard library: Python comes with a large standard library that provides a wide range of useful functions and modules for common programming tasks.
- Cross-platform: Python code can be run on a variety of platforms, including Windows, macOS, and Linux.
- What is the history of Python?
Answer: Python was created by Guido van Rossum in 1980s .While working at the National Research Institute for Mathematics and Computer Science in the Netherlands, Guido van Rossum started developing Python as a hobby project in December 1989, and released its first version, version 0.9.0, in February 1991. Guido wanted to create a programming language that was easy to learn, yet powerful enough to handle complex tasks. He named the language after the British comedy group Monty Python, as a tribute to their irreverent and offbeat humor.
The first version of Python was released in 1991, and the language quickly gained popularity for its simplicity, readability, and versatility. Python was initially used mainly for system administration tasks and scripting, but its popularity grew rapidly in the late 1990s and early 2000s as it became widely adopted in the scientific and academic communities.
- What are some significant milestones in the development of Python?
Answer: Here are some significant milestones in the development of Python:
- Version 1.0 – Python 1.0 came in market in 1994 with map, filter, reduce function
- Version 2.0 – Python 2.0 was released in 2000, and it included a number of improvements to the language, such as a garbage collector, list comprehensions, and support for Unicode.
- Version 3.0 – Python 3.0 was released in 2008, and it introduced a number of changes that were not backward-compatible with earlier versions of the language. These changes were designed to make the language more consistent and easier to use.
- The Python Software Foundation – In 2001, the Python Software Foundation (PSF) was created to promote, protect, and advance the Python programming language. The PSF is a non-profit organization that sponsors conferences, supports development efforts, and provides resources for the Python community.
- PEP 8 – In 2001, Python Enhancement Proposal (PEP) 8 was introduced. This proposal defined a set of coding conventions for Python code, including guidelines for formatting, naming, and commenting code. These conventions have become widely adopted within the Python community and are considered best practices for Python development.
- The rise of data science and machine learning – In recent years, Python has become increasingly popular for data science and machine learning applications. The language’s ease of use, large library of scientific computing tools, and strong community support have made it a favourite among data scientists and machine learning practitioners.
- What are some popular Python libraries and frameworks?
Answer: Python has a vast ecosystem of libraries and frameworks that are widely used in a variety of applications. Here are a few examples:
- NumPy – NumPy is a library used for numerical computing and to create multi-dimensional array. It provides fast and efficient arrays and matrices, as well as a range of mathematical functions for working with them.
- Pandas – Pandas used for data analysis. It provides data structures for working with tabular data, as well as functions for manipulating and analysing that data.
- Django – Django is a popular web framework for Python. It provides a high-level, easy-to-use interface for building web applications, with features such as URL routing, templates, and an ORM for database access.
- Flask – Flask is a lightweight web framework for Python. It provides a simple and flexible interface for building web applications, with features such as request routing and support for multiple HTTP methods.
- Scikit-learn – Scikit-learn used for machine learning. It provides a range of tools for building and training machine learning models, as well as functions for working with data and performing statistical analysis. Scikit-learn is widely used for tasks such as classification, regression, and clustering.
- TensorFlow – TensorFlow is another library for machine learning in Python. It provides a range of tools for building and training neural networks, as well as functions for working with numerical data and performing mathematical operations. TensorFlow used for computer vision technique and natural language processing also for speech recognition.
- What is a variable in Python?
Answer: Variable is used to store data of various types, such as numbers, strings, lists, and more.
- How do you declare a variable in Python?
Answer: To declare a variable in Python, you simply assign a value to a name using the = operator. For example, to declare a variable called x and assign it the value 5, you would write
x = 5
- What types of data can be stored in a Python variable?
Answer: Python variables can store various types of data, including numbers, strings, lists, tuples, dictionaries, and more.
- How do you check the type of a variable in Python?
Answer: You can check the type of a variable in Python using the type() function.
For example, type(x) would return <class ‘int’> if x is an integer.
- What is an identifier in Python ?
Answer: In programming, an identifier is a name that is used to identify a variable, function, class, method, module, or any other user-defined object. Identifiers in Python must adhere to certain rules:
- They must begin with a letter (either uppercase or lowercase) or an underscore (_).
- They can be followed by any combination of letters, underscores, and digits.
- They are case-sensitive, meaning that myVariable and myvariable are two different identifiers.
valid identifiers in Python:
- name
- my_name
- MyVariable
- _private_variable
- function_name
- class_name
It is important to choose meaningful and descriptive names for identifiers, as they can make code easier to read and understand. Additionally, it is best practice to avoid using reserved words as identifiers, such as if, else, for, while, and return, among others, as they have special meanings in Python and cannot be used as identifiers.
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- What are keywords in Python?
Answer: Keywords in Python are reserved words that have a special meaning and purpose in the language. They cannot be used as variable names or function names, as they have predefined meanings and are part of the language syntax.
- How many keywords are there in Python?
Answer: There are 35 keywords in Python 3.10 version. These are continue, def, del, elif, else, except , False, None, True, and, as, assert, async, await, break, class, , finally, for, from, global, if, import, in, is, lambda, nonlocal, not, or, pass, raise, return, try, while, with, and yield.
- What is a data type in Python?
Answer: A data type in Python defines the type of data that can be stored in a variable. Python has several built-in data types, including numeric, string, list, tuple, dictionary, set, and more.
- What is a numeric data type in Python?
Answer: Numeric data types in Python are used to represent numeric values, such as integers, floating-point numbers, and complex numbers. Python also supports the bool data type, which is used to represent boolean values True and False.
- What is a string data type in Python?
Answer: A string data type in Python is used to represent a sequence of characters. Strings can be enclosed in single or double quotes, and can be manipulated using various string methods.
- What is a list data type in Python?
Answer: A list data type in Python is used to represent a collection of ordered elements, which can be of any data type. Lists can be modified, appended, and sliced, and are enclosed in square brackets.
- What is a tuple data type in Python?
Answer: A tuple data type in Python is similar to a list, but is immutable, meaning it cannot be modified once it is created. Tuples are often used to represent fixed collections of data, and are enclosed in parentheses.
- What is a string in Python?
Answer: A string in Python is a sequence of characters enclosed in single or double quotes. Strings are a built-in data type in Python and can be used to represent textual data.
- How are strings manipulated in Python?
Answer: Strings in Python can be manipulated using various built-in string methods, such as upper(), lower(), strip(), replace(), and more. Additionally, strings can be concatenated using the + operator, and individual characters can be accessed using indexing.
- Can strings be modified in Python?
Answer: No, strings in Python are immutable, meaning they cannot be modified once they are created. Any manipulation of a string actually creates a new string object.
- How can you check if a string contains a substring in Python?
Answer: You can check if a string contains a substring in Python using the in keyword. For example, the expression “hello” in “hello world” would return True, while the expression “foo” in “hello world” would return False. You can also use the find() method to return the index of the first occurrence of a substring, or -1 if it is not found.
- Can you concatenate strings in Python?
Answer: Yes, you can concatenate strings in Python using the + operator. For example, “hello” + “world” would result in the string “helloworld”.
- How can you convert a string to uppercase in Python?
Answer: You can convert a string to uppercase in Python using the upper() method. For example, “hello”.upper() would result in the string “HELLO”.
- How can you split a string into a list of substrings in Python?
Answer: You can split a string into a list of substrings in Python using the split() method. For example, “hello world”.split() would result in the list [“hello”, “world”]. You can also specify a delimiter to split on, such as “hello,world”.split(“,”), which would result in the list [“hello”, “world”].
- How can you format a string in Python?
Answer: You can format a string in Python using f-strings or the format() method. For example, name = “Alice”; f”Hello, {name}!” would result in the string “Hello, Alice!”. Another way, “Hello, {}!”.format(name)
- How can you remove whitespace from the beginning and end of a string in Python?
Answer: You can remove whitespace from the beginning and end of a string in Python using the strip() method. For example, ” hello world “.strip() would result in the string “hello world”. If you only want to remove whitespace from the beginning or end of a string, you can use the lstrip() or rstrip() methods, respectively.
- How can you join multiple strings together in Python?
Answer: You can join multiple strings together in Python using the join() method. This method takes an iterable of strings and returns a new string with all the strings concatenated together. For example, ” “.join([“hello”, “world”]) would result in the string “hello world”.
- How can you compare two strings in Python?
Answer: You can compare two strings in Python using the comparison operators ==, !=, <, <=, >, and >=. These operators compare the strings lexicographically, meaning they compare each character in the strings according to their Unicode values.
- How can you check if a string is empty in Python?
Answer: You can check if a string is empty in Python by using the len() function. An empty string has a length of 0, so len(my_string) == 0 would return True if my_string is empty.
- How can you reverse a string in Python?
Answer: You can reverse a string in Python using string slicing. For example, “hello”[::-1] would result in the string “olleh”. This works by slicing the string from the beginning to the end, with a step of -1, which reverses the order of the characters.
- How can you check if a string contains only digits in Python?
Answer: You can check if a string contains only digits in Python using the isdigit() method. For example, “123”.isdigit() would return True, while “abc123”.isdigit() would return False.
- What is a multiple line string in Python?
Answer: A multiple line string in Python is a string that spans multiple lines and is enclosed in triple quotes (“”” or ”’). This allows for more readable and maintainable code when dealing with long strings or multi-line text.
- How are multiple line strings created in Python?
Answer: Multiple line strings are created in Python by enclosing the text in triple quotes (“”” or ”’). For example,
my_string = “””Hello World
by “””
- What is the input() function in Python?
Answer: The input() function in Python is used to accept user input from the command line. When called, it displays a prompt message and waits for the user to enter input, which is then returned as a string.
- How is the input() function called in Python?
Answer: The input() function is called by simply writing input() in the code. Optionally, you can pass a prompt message to the function to be displayed before accepting input. For example, name = input(“Enter your name: “).
- What is the data type of the value returned by the input() function?
Answer: The data type of the value returned by the input() function is always a string, even if the user enters a number or other type of data. If you want to use the input as a different data type, you’ll need to cast it using functions like int(), float(), etc.
- What is an f-string in Python?
Answer: An f-string (short for “formatted string literal”) in Python is a way to embed expressions inside string literals using string interpolation. They start with the letter ‘f’ or ‘F’, followed by a string literal that may contain replacement fields, which are expressions delimited by curly braces.
- How are f-strings created in Python?
Answer: f-strings are created by enclosing the expression to be evaluated in curly braces within a string literal, preceded by the letter ‘f’.
For example, name = “Alice”; f”Hello, {name}!” would result in the string “Hello, Alice!”.
- What is typecasting in Python?
Answer: Typecasting (also known as type conversion) in Python refers to the process of converting a value from one data type to another.
- How can you perform typecasting in Python?
Answer: You can perform typecasting in Python using built-in type conversion functions, such as int(), float(), str(), bool(), and list(). For example, float(3) would result in the floating-point number 3.0.
- What is swapping in Python?
Answer: In Python, you can swap the values of two variables using a temporary variable or by using tuple packing and unpacking. Here are examples of both methods:
1)method-1
a = 5
b = 10
# swapping by using temp
temp = a
a = b
b = temp
2) method-2
# initializing two variables
a = 5
b = 10
# swapping the values using tuple packing and unpacking
a, b = b, a
- What are operators in Python?
Answer: Operators in Python are special symbols or keywords that are used to perform operations on values or variables.
- What are the different types of operators in Python?
Answer: The different types of operators in Python are arithmetic operators, comparison operators, logical operators, assignment operators, identity operators, and membership operators.
- What are arithmetic operators in Python?
Answer: Arithmetic operators used to perform mathematical operations like addition ,division many more. The arithmetic operators are + (addition) for addition of values, – (subtraction), * (multiplication), / (division), % (modulus) to get remainder , ** (exponentiation), and // (floor division) to get just integer part of division.
- What are logical operators in Python?
Answer: Logical operators in Python are used to combine two or more Boolean expressions and return a Boolean value. The and operator returns True if both expressions are True, the or operator returns True if at least one expression is True, and the not operator returns the opposite of the expression’s value.
- What are assignment operators in Python?
Answer: Assignment operators in Python are used to assign values to variables. The assignment operators are = (simple assignment), += (addition assignment), -= (subtraction assignment), *= (multiplication assignment), /= (division assignment), %= (modulus assignment), **= (exponentiation assignment), and //= (floor division assignment).
- What are identity operators in Python?
Answer: Identity operators in Python are used to compare the memory locations of two objects. The identity operators are is (returns True if identity of object are the same) and is not (returns True if identity of object are not the same).
- What are membership operators in Python?
Answer: Membership operators in Python are used to check a given value is present or not in a given sequence (such as a string, list, or tuple). The membership operators are in (returns True if the value is present in the sequence) and not in (returns True if the value is not present in the sequence).
- What is operator precedence in Python?
Answer: Operator precedence means the operators are evaluated in specific order. Operations with higher precedence are given priority and evaluated first, before operations with lower precedence. For example, multiplication (*) has a higher precedence than addition (+), so 2 + 3 * 4 would evaluate to 14 instead of 20 because the multiplication is performed first.
- Can you overload operators in Python?
Answer: Yes, you can overload operators in Python for custom classes using special methods. For example, you can define the __add__ method to overload the + operator for a custom class, allowing instances of the class to be added together using the + operator. However, some operators (such as the logical operators and, or, and not) cannot be overloaded in Python.
- What is range data type?
Answer: range() is a built-in function in Python that returns an immutable sequence of numbers. It is commonly used for looping a specific number of times in a for loop.
The syntax for using range() is range(start, stop, step), where start is the starting value (inclusive), stop is the stopping value (exclusive), and step is the increment (default is 1). If they are not explicitly specified, the programming language will assign default values to them. The default value is 0 for start and 1 for step parameter.
- What is indexing ?
Answer: In Python, indexing is a way to retrieve specific elements or characters from a sequence, such as a string, list, or tuple, by their position or index in the sequence. Each element or character in the sequence is assigned an index number, starting from 0 for the first element or character. Each element in the sequence is assigned an index number starting from 0 for the first element, 1 for the second element, and so on.
s = “hello”
print(s[1]) # output: ‘e’
- What is sequence data types in python
Answer: In Python, a sequence data type is a type of data that represents an ordered collection of elements or items. There are three built-in sequence data types in Python:
- Lists: Lists are ordered collections of elements, which can be of different data types. They are created using square brackets ([]) and elements are separated by commas. Elements can be added, removed, or modified using various methods and indexing.
- Tuples: Tuples are similar to lists, but they are immutable, meaning that their elements cannot be changed once they are created. We can create tuple using parentheses (()) and elements are separated by commas.
- Strings: Strings are sequences of characters, which can be letters, numbers, or symbols. They are created using single quotes (‘) or double quotes (“) and can be indexed and sliced like lists. However, unlike lists and tuples, strings are immutable, meaning that their characters cannot be changed once they are created.
Sequence data types are important in Python because they allow you to represent and manipulate collections of data in a structured and organized way
- What is container data type ?
Answer: In Python, a container data type is a type of data that holds other objects or values. These containers are used to group related data together in a structured and organized way, which makes it easier to manage and manipulate the data.
Some examples of container data types in Python include:
- Strings: Strings are sequences of characters, which can be letters, numbers, or symbols. They are created using single quotes (‘) or double quotes (“)
- Lists: Lists are one of the most commonly used container data types in Python. They are mutable, ordered collections of elements that can be of different data types.
- Tuples: Tuples are similar to lists, but they are immutable, meaning that their elements cannot be changed once they are created.
- Sets: Sets are unordered collections of unique elements. They are mutable and can be used for operations such as union, intersection, and difference.
- Dictionaries: Dictionaries are mutable collections of key-value pairs. They are unordered, and the keys must be unique and immutable.
- Arrays: Arrays are mutable collections of elements of the same data type.
- What is the id() function in Python?
Answer: The id() function in Python returns a unique identifier (an integer) for the given object. The identifier is guaranteed to be unique and constant for the lifetime of the object, which means that it can be used to compare objects for identity
x = 42
print(id(x)) # output: some integer value
- What is the del keyword in Python?
Answer: The del keyword in Python is used to delete an object or a reference to an object. When you delete an object, it is removed from memory and cannot be accessed anymore. When you delete a reference to an object, the reference is removed, but the object itself may still exist in memory if there are other references to it
- What is an if-else statement in Python?
Answer: An if-else statement in Python is a control flow statement that allows you to execute different code blocks depending on whether a certain condition is true or false.
if condition:
# If the condition is true this block will get executed
else:
# If the condition is true this block will get executed
For example:
x = 42
if x < 0:
print(“x is negative”)
else:
print(“x is non-negative”)
In the above example, the if-else statement checks if the variable x is negative or non-negative and prints a corresponding message.
- What is a for loop in Python?
Answer: A for loop in Python is a way to iterate over a sequence of values (such as a list, tuple, or string) and execute a code block for each value.
for variable in sequence:
# block of code
For example:
name = [“apple”, “banana”, “cherry”]
for i in name:
print(i)
In the above example, the for loop iterates over the list of name and prints each fruit.
- What is a while loop in Python?
Answer: A while loop in Python is a way to execute a code block repeatedly while a certain condition is true.
For example:
x = 1
while x < 10:
print(x)
x = x + 1
In the above example, the while loop executes the code block as long as the variable x is less than 10, and prints the value of x in each iteration.
- How can you use if-else statements and loops together in Python?
Answer: You can use if-else statements and loops together to execute different code blocks based on certain conditions while iterating over a sequence of values. For example:
numbers = [1, 2, 3, 4, 5]
for number in numbers:
if number % 2 == 0:
print(f”{number} is even”)
else:
print(f”{number} is odd”)
In the above example, the for loop iterates over a list of numbers and uses an if-else statement to check if each number is even or odd, and prints a corresponding message.
- What is the break statement in Python?
Answer: The break statement in Python is a control flow statement that allows you to exit a loop prematurely. The break statement in programming is used to exit a loop prematurely when a certain condition is met. Break stops nest all iteration and moves on to the next statement outside the loop. Here is an example:
numbers = [1, 2, 3, 4, 5]
for number in numbers:
if number == 3:
break
print(number)
In the above example, the break statement is used inside a for loop to terminate the loop prematurely when the value of number is equal to 3.
- What is the continue statement in Python?
Answer: The continue statement in Python is a control flow statement that allows you to skip the current iteration of a loop and move on to the next iteration. When the continue statement is executed inside a loop, it causes the loop to skip the current iteration and move on to the next iteration. The continue statement is often used in combination with a conditional statement to skip certain iterations of a loop when a certain condition is met. Here is an example:
numbers = [1, 2, 3, 4, 5]
for number in numbers:
if number == 3:
continue
print(number)
In the above example, the continue statement is used inside a for loop to skip the iteration when the value of number is equal to 3.
- What is the pass statement in Python?
Answer: The pass statement in Python is a null statement that does nothing. It is used as a placeholder when you need to write code that does nothing, but you need to have some code in the block to avoid a syntax error. The pass statement is often used when you are writing code that you plan to fill in later. Here is an example:
if x < 0:
pass
In the above example, you need to have some code in the block after the if statement to avoid a syntax error. However, you have not yet written the code to handle negative numbers.
- What is a list?
Answer: A list is a collection of items that are ordered and indexed, which can be of any data type, such as numbers, strings, or even other lists.
- How do you create a list in Python?
Answer: You can create a list in Python by enclosing a comma-separated sequence of items within square brackets, like this:
my_list = [1, 2, 3, “four”, “five”]
- How do you access elements of a list in Python?
Answer: You can access individual elements of a list in Python by using square brackets with the index number of the element you want to access, like this:
my_list = [1, 2, 3, “four”, “five”]
print(my_list[0]) # Output: 1
print(my_list[3]) # Output: “four”
- Can you modify elements of a list in Python?
Answer: Yes, you can modify elements of a list in Python by assigning a new value to the element’s index, like this:
my_list = [1, 2, 3, “four”, “five”]
my_list[3] = “FOUR”
print(my_list)
# Output: [1, 2, 3, “FOUR”, “five”]
- How do you add elements to a list in Python?
Answer: You can add elements to a list in Python using the append() method to add an item to the end of the list, or the insert() method to add an item at a specific index, like this:
list1 = [1, 2, 3]
list1.append(4)
print(list1)
# Output: [1, 2, 3, 4]
list1.insert(2, “apple”)
print(list1)
# Output: [1, 2, “apple”, 3, 4]
- How do you remove elements from a list in Python?
Answer: You can remove elements from a list in Python using the remove() method to remove the first occurrence of a specified item, or the pop() method to remove an item at a specific index and return its value, like this:
list2 = [1, 2, “apple”, 3, 4]
list2.remove(“apple”)
print(list2) # Output: [1, 2, 3, 4]
removed_item = list2.pop(2)
print(list2)
# Output: [1, 2, 4]
print(removed_item) # Output: 3
- How do you check if an element is in a list in Python?
Answer: You can check if an element is in a list in Python using the in keyword, like this:
list4 = [1, 2, 3, 4]
if 3 in list4:
print(“3 is in the list”)
else:
print(“3 is not in the list”)
- How to perform sorting of a list in Python?
Answer: You can sort a list in Python using the sort() method to sort the list in place, or the sorted() function to return a sorted copy of the list, like this:
list3= [3, 2, 1, 4]
list3.sort()
print(list3)
# Output: [1, 2, 3, 4]
my_sorted_list = sorted(list3)
print(my_sorted_list)
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- What is list comprehension?
Answer: List comprehension is a concise and efficient way of creating a new list by applying an expression to each element of an existing list or another iterable object.
- What is the syntax for list comprehension in Python?
Answer: The syntax for list comprehension in Python is enclosed within square brackets and consists of three parts: the expression to apply to each element, the loop variable(s), and the iterable object:
new_list = [expression(variable) for variable in iterable]
- Explain shallow copy and deep copy in Python.
Answer: In Python, a shallow copy of an object creates a new object with the same values as the original object, but with references to the same memory locations for mutable sub-objects. A deep copy, on the other hand, creates a completely new object with new memory locations for all sub-objects, recursively copying all sub-objects to new memory locations.
- What is a tuple in Python?
Answer: A tuple is an immutable ordered collection of items in Python. Tuples are typically used to represent a collection of related values that should not be changed, such as a set of coordinates or a date and time.
- How do you create a tuple in Python?
Answer: You can create a tuple in Python by enclosing a comma-separated sequence of elements in parentheses, like this:
my_tuple = (1, 2, 3)
- What is a set in Python?
Answer: A set is an unordered unindexed collection of unique elements in Python. Sets are similar to lists and tuples, but they do not allow duplicate elements. Sets are typically used to perform mathematical operations such as union, intersection, and difference.
- How to create a set in Python?
Answer: You can create a set by using a comma-separated sequence of items in curly braces, like this:
set1 = {1, 2, 3}
- What is a dictionary in Python?
Answer: A dictionary is an unordered collection of key-value pairs in Python. Each key-value pair in a dictionary is called an item, and keys must be unique and immutable. Dictionaries are typically used to represent a set of related values that can be accessed by name rather than by position.
- How can you create a dictionary in Python?
Answer: You can create a dictionary in Python by enclosing a comma-separated sequence of key-value pairs in curly braces, like this:
newdict = {‘key_1’: ‘value_1’, ‘key_1’: ‘value_2’, ‘key_3’: ‘value_3’}
- Explain the difference between a list and a tuple
Answer: 
- Can you modify a tuple in Python?
Answer: No, you cannot modify a tuple in Python. Tuples are immutable data types. Their values cannot be changed.
- What are some use cases for dictionaries in Python?
Answer: Dictionaries are commonly used in Python for the following purposes:
- To represent collections of related data that are not easily represented as lists or tuples.
- To represent key-value mappings, such as the properties of an object.
- To store and retrieve data in a more efficient manner than using lists or tuples.
- What is a function in Python?
Answer: A function in Python is a block of code that performs a specific task or action. Functions can take arguments as input, perform operations on them, and return a result. Functions can be defined by the def keyword followed by the function name and its arguments in parentheses, like this:
def my_function(arg1, arg2):
result = arg1 + arg2 # Function body
return result
- How do you call a function in Python?
Answer: To call a function in Python, you simply use its name followed by parentheses and any arguments that it takes, like this:
my_result = my_function(1, 2)
- What is the difference between a function definition and a function call?
Answer: A function definition is the code that defines a function, including its name, arguments, and body. A function call is when you actually execute the function by providing any necessary arguments. For example, this is a function definition:
def my_function(arg1, arg2):
result = arg1 + arg2 # Function body
return result
And this is a function call:
my_result = my_function(1, 2)
- Can a function return multiple values in Python?
Answer: Yes, a function can return multiple values in Python by returning a tuple of values. For example:
def my_function():
return 1, 2, 3 # Function body
a, b, c = my_function()
- What is a lambda function in Python?
Answer: A lambda function in Python is a small anonymous function that can take any number of arguments, but can only have one expression. Lambda functions are useful when you need to define a function for a specific purpose and don’t want to define a named function for it. Lambda functions are defined using the lambda keyword, like this:
my_lambda = lambda x: x * 2
- What is recursion in Python?
Answer: Recursion in Python is a technique where a function calls itself in order to solve a problem. Recursion is useful when you need to solve a problem that can be broken down into smaller subproblems of the same type. For example, here’s a recursive function that calculates the factorial of a number:
def factorial(n):
if n == 1:
return 1
else:
return n * factorial(n – 1)
- What are some best practices for writing functions in Python?
Answer: Some best practices for writing functions in Python include:
- Giving functions descriptive names that accurately describe what they do.
- Including a docstring at the beginning of the function that describes what it does and how to use it.
- Avoiding global variables and using function arguments instead.
- Using default argument values to make functions more flexible.
- Using meaningful variable names within functions.
- What is a namespace in Python?
Answer: In Python, a namespace is a container that holds a set of identifiers (variable names, function names, class names, etc.) and maps them to their corresponding objects (values, functions, classes, etc.). It’s a way of organizing objects in Python so that they can be easily accessed and used. Namespaces are used to avoid naming conflicts between different objects, and to make it easy to refer to objects in your code.
- What are the different types of namespaces in Python?
Answer: There are several types of namespaces in Python, including:
The built-in namespace, which contains all the built-in functions and variables in Python.
The global namespace, which contains all the variables and functions defined in the top-level of a module or script.
Local namespaces, which are created whenever a function is called and contain the local variables and function arguments.
The non-local namespace, which contains variables defined in an enclosing function.
- How do namespaces work in Python?
Answer: In Python, namespaces are implemented as dictionaries. Whenever you create a variable or function in Python, it is stored in a namespace. When you try to access a variable or function in your code, Python looks for it in the local namespace first, and if it’s not found there, it searches in the global namespace, and after that in the built-in namespace.
- How are namespaces created in Python?
Answer: Namespaces in Python are created automatically when you create a variable or function. When you create a variable or function in Python, it is automatically added to the current namespace
- What is a module in Python?
Answer: In Python, a module is a file that contains Python code, typically containing functions, classes, and variables, that can be imported and used in other Python scripts or modules. Modules allow you to organize and reuse code, and provide a way to encapsulate related functionality.
- What are some built-in modules in Python?
Answer: Python comes with a large number of built-in modules that provide additional functionality. Some examples of built-in modules include:
math: provides mathematical functions and constants
random: provides functions for generating random numbers
sys: provides access to system-specific parameters and functions
datetime: dates and times related methods
re: provides regular expression matching operations
- How do you import a module in Python?
Answer: You can import a module in Python using the import statement.
import math
This makes all the functions and variables in the math module available in your script or module. You can then access these functions and variables using the dot notation:
x = math.sin(0.5)
You can also use the as keyword to alias a module name:
import math as m
x = m.sin(0.5)
- How to install module in python
Answer: To install a module in Python, you can use a package manager called pip, which is included with most Python installations. Here are the general steps to install a module using pip:
- Open command prompt on your computer.
- Use the pip install command followed by the name of the module you want to install.
Example
pip install requests
This command will download and install the latest version of the requests module from the Python Package Index (PyPI), along with any dependencies it requires.
- What is pip in python
Answer: pip is a package manager that is used to install libraries also can manage external libraries and modules. It is the most commonly used tool for managing Python packages, and is included with most Python installations.
pip allows you to easily install, upgrade, and remove Python packages from the Python Package Index (PyPI), as well as from other package indexes and local archives. It also provides a way to manage dependencies between packages, ensuring that all required packages are installed and up-to-date.
- What is OOPs?
Answer: Object-Oriented Programming (OOPs) is a programming paradigm that uses objects to represent and manipulate data, and the relationships between them. It emphasizes the concepts of encapsulation, inheritance, and polymorphism to create reusable and modular code.
- What is class in python ?
Answer: Class is a blueprint also you can say that is a design or template foe an object . It defines a set of attributes and methods that are shared by all instances of the class, and can be used to create new instances of the class.
- What is an object in Python?
Answer: Object means an instance of a class. It has its own unique set of attributes and can call the methods defined in the class.
- What is encapsulation in OOPs?
Answer: Encapsulation is the concept of hiding the internal details of an object from the outside world, and only exposing a public interface for interacting with the object. In Python, this is often achieved using access modifiers such as private or protected variables and methods.
- What is inheritance in OOPs?
Answer: Inheritance is the concept of creating a new class that inherits the attributes and methods of an existing class. The new class, known as the subclass or derived class, can add or override methods and attributes as needed, while still having access to the functionality of the original class, called superclass. Superclass means Base class
- What is polymorphism in OOPs?
Answer: Polymorphism is the concept of using a single interface to represent multiple related objects or classes. In Python, this is often achieved using method overriding or method overloading.
- How do you define a class in Python?
Answer: Use the class keyword, followed by the name of the class and a colon, and then the class body, which contains the attributes and methods of the class. Here is an example:
class Person:
def __init__(self, name, age):
self.name = name
self.age = age
def say_hello(self):
print(“Hello, my name is”, self.name)
- How do you create an object of a class in Python?
Answer: To create an object of a class in Python, you call the class name as if it were a function, and assign the result to a variable. Here is an example:
person1 = Person(“raj”, 25)
person2 = Person(“sana”, 30)
- How do you access attributes and methods of an object in Python?
Answer: To access attributes and methods of an object in Python, you use dot notation, with the object name followed by a period and then the attribute or method name. Here is an example:
print(person1.name)
person2.say_hello()
- What is the self parameter in Python classes?
Answer: The self parameter is a reference to the instance or object of the class that a method is called on. It is the first parameter in any instance method of a class, and is conventionally named self. By convention, instance variables are also prefixed with self. to distinguish them from local variables.
- What is a constructor in Python classes?
Answer: A constructor is a special method in a Python class that is called when an object is created. It used to initialize the attributes of the object or instance. In Python, the constructor method is named __init__, and takes the self parameter and any other parameters needed to initialize the object.
- What is a destructor in Python classes?
Answer: A destructor is a special method in a Python class that is called when an object is destroyed or garbage collected. In Python, the destructor method is named __del__, and can be used to perform any cleanup tasks needed before the object is destroyed.
- What is method overloading in Python?
Answer: Method overloading is the concept of defining multiple methods with the same name but different parameters in a class. However, Python does not support method overloading directly, since it is dynamically typed and does not require explicit type declarations for parameters or return values.
- What is method overriding in Python?
Answer: Method overriding is the concept of redefining a method in a subclass with the same name and parameters as a method in the superclass. This allows the subclass to provide a different implementation for the method, while still using the same method name and parameters as the superclass.
- What is a static method in Python classes?
Answer: A static method is a method in a Python class that does not depend on the state of the object or class, and can be called without creating an instance of the class. To implement static method @staticmethod decorator is used and don’t pass the self parameter.
- What is a class method in Python classes?
Answer: A class method is a method in a Python class that operates on the class itself, rather than on individual instances of the class. To implement classmethod use @classmethod decorator and pass cls parameter and it refers to the class itself.
- What is inheritance hierarchy in Python classes?
Answer: Inheritance hierarchy is the arrangement of classes in a hierarchy, where each class is derived from a superclass or base class, and can have one or more subclasses or derived classes. In Python, the super() function is used to access the superclass of a derived class.
- What is the difference between a public and private attribute in Python classes?
Answer: In Python, there is no strict distinction between public and private attributes, since all attributes are accessible from outside the class. However, by convention, attributes that are intended to be private or protected are prefixed with an underscore, such as _name or __age. This indicates that they are intended to be used only within the class or its subclasses, and should not be accessed or modified directly from outside the class.
- What is a decorator in Python?
Answer: A decorator is a function or class that is used to modify or extend the behavior of another function or class. Decorators are applied using the @ syntax, and can be used to add functionality such as logging, caching, or authentication to a function or class.
- What is the difference between is and == operators in Python?
Answer: The is operator tests whether two objects are the same object in memory, while the == operator tests whether two objects are equal in value. is checks for identity of operands and == checks for value or equality. It is possible for two objects to be equal but not identical, or identical but not equal.
- What is exception handling in Python?
Answer: Exception handling is a mechanism in Python to handle runtime errors or exceptional conditions that may occur during program execution. When an error occurs, Python raises an exception, which can be caught and handled by the program to prevent the program from crashing.
- How do you catch exceptions in Python?
Answer: In python, we have the try and except statements to handle exception. In try block write the code that may raise an exception and in the except block you can write the code to handle the exception. If an exception occurs in the try block, the program jumps to the except block to handle the exception.
- What is the syntax for a try and except block in Python?
Answer: The syntax for a try and except block in Python is as follows:
try:
# Write a code that raise an exception
except ExceptionType:
# code to handle the exception
In this syntax, ExceptionType is the type of exception that you want to catch. You can replace ExceptionType with any built-in or custom exception class that you want to catch.
- How do you raise an exception in Python?
Answer: To raise an exception in Python, you can use the raise statement. The raise statement takes an exception object as its argument, which can be a built-in or custom exception class. Here’s an example:
x = 10
if x > 7:
raise ValueError(“x is not valid “)
In this example, if x is greater than 7, the program raises a ValueError with the message “x is not valid “.
- What is duck typing in Python?
Answer: Duck typing is a programming concept in Python where the type or class of an object is less important than its behavior. If an object quacks like a duck, walks like a duck, and looks like a duck, then it’s a duck. In other words, Python does not require explicit type declaration and allows objects of different types to be used interchangeably as long as they have the same method or attribute signatures.
- How is duck typing different from traditional typing?
Answer: In traditional typing, the type of an object is explicitly declared and enforced at compile-time or runtime. This means that only objects of a specific type can be used in a given context. In contrast, duck typing does not require explicit type declaration and allows objects of different types to be used interchangeably as long as they have the same method or attribute signatures.
- What is multi-threading in Python?
Answer: Multi-threading is a technique in Python that allows multiple threads of execution to run concurrently within a single process. Each thread is a separate flow of execution.
- How do you create a thread in Python?
Answer: To create a thread in Python, you can use the threading module. First, import the module, and then create a new Thread object, passing in the function you want to execute in the new thread as an argument:
import threading
def my_function():
# code to be executed in the new thread
my_thread = threading.Thread(target=my_function)
- What is a race condition in multi-threaded programming?
Answer: A race condition occurs in multi-threaded programming when two or more threads access a shared resource concurrently, and the outcome of the program depends on the order in which the threads execute. This can lead to unpredictable behavior and bugs that are difficult to reproduce and debug. Race conditions can be avoided by using synchronization primitives to coordinate access to shared resources.
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- What is pickling in Python?
Answer: In Python, pickling is the process of serializing (i.e., converting) a Python object into a stream of bytes, which can be saved to a file or transferred over a network. The byte stream can later be unpickled to reconstruct the original Python object hierarchy.
- How do you pickle an object in Python?
Answer: To pickle an object in Python, you can use the pickle module. First, import the module and then call the pickle.dump() function, passing in the object you want to pickle and a file object to write the byte stream to:
import pickle
my_object = {‘name’: ‘Alice’, ‘age’: 30}
with open(‘my_object.pickle’, ‘wb’) as f:
pickle.dump(my_object, f)
- What is unpickling in Python?
Answer: Unpickling is the process of converting a byte stream that was created by pickling back into a Python object hierarchy.
- How do you unpickle an object in Python?
Answer: To unpickle an object in Python, you can use the pickle module. First, open the file containing the pickled byte stream, and then call the pickle.load() function to load the object back into memory:
import pickle
with open(‘my_object.pickle’, ‘rb’) as f:
my_object = pickle.load(f)
- What is an iterator in Python?
Answer: An iterator is an object in Python that can be iterated upon, meaning that it can be used in a for loop. To be an iterator, an object must implement the __iter__() and __next__() methods.
- What is a generator in Python?
Answer: A generator is a special type of iterator that is defined using a yield statement instead of the __next__() method. When you call a generator function, it returns a generator object, which can be used to iterate over a sequence of values.
- What is the difference between an iterator and a generator in Python?
Answer: An iterator is any object that can be iterated upon, whereas a generator is a specific type of iterator that is defined using a yield statement. While an iterator can be created using any object that implements the __iter__() and __next__() methods, a generator is created using a special type of function called a generator function, which is defined using the yield keyword.
- What is docstring in Python ?
Answer: Docstrings in Python are strings that are used to document modules, classes, functions, and methods. They are enclosed in triple quotes, either single or double quotes. Docstrings provide a way to describe what a module, class, function, or method does and how it should be used.
def add_numbers(x, y):
“””This is my first function.
Name-:Suraj Kale
date 2/2/22″””
return x + y
- What is NumPy?
Answer: NumPy is a Python library that is used for working with arrays. It provides a powerful set of functions and tools for manipulating and performing operations on arrays, as well as mathematical functions for numerical analysis.
- What is the difference between a list and a NumPy array?
Answer: A list in Python can contain elements of different types, and it is not optimized for numerical operations. A NumPy array, on the other hand, contains elements of the same type and is optimized for numerical operations, making it much faster and more efficient than a list for numerical computation.
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