What is a Python : A Python was created and first released in 1991 by Guido van Rossum. It is a high-level, general-purpose programming language that emphasizes code readability and provides easy-to-use syntax. Several developers and programmers prefer using Python for their programming needs due to its simplicity. After 30 years, Van Rossum stepped down as the leader of the community in 2018. 

Python interpreters are available for many operating systems. CPython, the reference implementation of Python, is open-source software and has a community-based development model, as do nearly all of its variant implementations. Python and CPython are managed by the non-profit Python Software Foundation.

Why Python : A Python is a high-level, general-purpose programming language. Python is a programming language that may be used to create desktop GUI apps, websites, and online applications. Python, as a high-level programming language, also allows you to concentrate on the application’s essential functionality while it handles routine programming duties. The basic grammar limitations of the programming language make it considerably easier to maintain the code base intelligible and the application manageable.

To Install Python, first, go to Anaconda.org and click on “Download Anaconda”. Here, you can download the latest version of Python. After Python is installed, it is a pretty straightforward process. The next step is to power up an IDE and start coding in Python.

Python is a new field and most popular programming language and may be used to create any application, websites and software, data analysis and many more.. Here is the details in required field.

Web Applications : We can use Python Language to develop web applications. It contains HTML and XML libraries, JSON libraries, email processing libraries, request libraries, Feedparser libraries, and other internet protocols. Example : Instagram uses Django, a Python web framework.

Desktop GUI Applications : The Graphical User Interface (GUI) is a user interface that allows for easy interaction with any programme. Python contains the Tk GUI framework for creating user interfaces.

Console-based Application : The command-line or shell is used to execute console-based programmes. These are computer programmes that are used to carry out orders. This type of programme was more common in the previous generation of computers. It is well-known for its REPL (Read-Eval-Print Loop), which makes it ideal for command-line applications.

Python has a number of free libraries and modules that help in the creation of command-line applications. There are additional advanced libraries that may be used to create standalone console applications.

Software Development : Python is useful for the software development process. It’s a support language that may be used to establish control and management, testing, and other things.

Scientific and Numeric : Python is an excellent programming language for artificial intelligence and machine learning applications. This is the time of artificial intelligence, in which a machine can execute tasks as well as a person can. It has a number of scientific and mathematical libraries that make doing difficult computations simple.

The machine learning algorithms into practice requires a lot of arithmetic. Numpy, Pandas, Scipy, Scikit-learn, and other scientific and numerical Python libraries are available. If you know how to use Python, you’ll be able to import libraries on top of the code. Some  machine library frameworks are SciPy, Scikit, NumPy, Pandas, Matplotlib etc.

Audio or Video-based Applications : Python is a versatile programming language that may be used to construct multimedia applications. Some examples like  TimPlayer, cplay, and other multimedia programmes written in Python Language.

3D CAD Applications : Engineering-related architecture is designed using CAD (Computer-aided design). It’s used to create a three-dimensional visualization of a system component. The following features in Python can be used to develop a 3D CAD application. Example: Fandango, CAMVOX, HeeksCNC, AnyCAD, RCAM etc.

Enterprise Applications : Python may be used to develop apps for usage within a business or organization. Example : OpenERP, Tryton, Picalo all these real-time applications.

Image Processing Application : Python has a lot of libraries for working with pictures. Example : OpenCV, Pillow, and SimpleITK are all image processing libraries present in python.

Every object in Python functions within a scope. A scope is a block of code where an object in Python remains relevant.

Namespaces uniquely identify all the objects inside a program. These namespaces also have a scope defined for them where you could use their objects without any prefix. A few examples of scope will be created during code execution in Python are 

• A local scope refers to the local objects available in the current function.
• A global scope refers to the objects available throughout the code execution since their inception.
• A module-level scope refers to the global objects of the current module accessible in the program.
• An outermost scope refers to all the built-in names callable in the program. The objects in this scope are searched last to find the name referenced

Some of the benefits of Python are 

• Python is a general-purpose programming language that has a simple, easy-to-learn syntax that emphasizes readability and therefore reduces the cost of program maintenance. Moreover, the language is capable of scripting, is completely open-source, and supports third-party packages encouraging modularity and code reuse.
• Its high-level data structures, combined with dynamic typing and dynamic binding, attract a huge community of developersfor Rapid Application Development and deployment.

Python is a general-purpose dynamic programming language that is high-level and interpreted. Its architectural framework prioritizes code readability and utilizes indentation extensively. Some Advantages of Python are:

• Python is Interpreted language

Interpreted: Python is an interpreted language. It does not require prior compilation of code and executes instructions directly.

• Python is free to use and has a large open-source community.

Free and open source: It is an open-source project which is publicly available to reuse. It can be downloaded free of cost.

• It is Extensible

Extensible: It is very flexible and extensible with any module.

• Object-oriented

Object-oriented: Python allows to implement the Object-Oriented concepts to build application solution.

• It has Built-in data structure

Built-in data structure: Tuple, List, and Dictionary are useful integrated data structures provided by the language.

• Readability
• High-Level Language
• Cross-platform

Portable:

One of the best features of Python is its portability: it can and does run on any platform without having to change the requirements. It provides a lot of functionality in lesser lines of code compared to other programming languages like Java, C++, etc.

• Several support libraries are available (NumPy for numerical calculations, Pandas for data analytics, etc)

Python is one of the most popular programming languages used by data scientists and AIML professionals. This popularity is due to the following key features of Python:

• Python is easy to learn due to its clear syntax and readability
• Python is easy to interpret, making debugging easy
• Python is free and Open-source
• It can be used across different languages
• It is an object-oriented language that supports concepts of classes
• It can be easily integrated with other languages like C++, Java, and more

Self is an instance or an object of a class. Using this keyword, you can access the attributes and methods of the class in python. It binds the attributes with the given arguments. self is used in different places and often thought to be a keyword. But unlike in C++, self is not a keyword in Python.

Python helps to differentiate between the methods and attributes of a class with local variables.

The self-variable in the init method refers to the newly created object while in other methods, it refers to the object whose method was called.

__init__ is a contructor method in Python and is automatically called to allocate memory when a new object/instance is created. All classes have a __init__ method associated with them. It helps in distinguishing methods and attributes of a class from local variables.

# class definition
class Student:
   def __init__(self, fname, lname, age, section):
       self.firstname = fname
       self.lastname = lname
       self.age = age
       self.section = section
# creating a new object
stu1 = Student("Sara", "Ansh", 22, "A2")

Keywords in Python are reserved words that are used as identifiers, function names, or variable names. They help define the structure and syntax of the language.  There are arround 33 keywords i.e., Python 3.8. A list of all the keywords are 

none, continue, for, as, if, else, elif, or, yield, lambda, try, class, finally, is, return, from, nonlocal, while, for, global, not, with, true, false, def, import, pass, and, del, break, except, assert

List and tuple are data structures in Python that may store one or more objects or values.It hold numerous items in a single variable and are defined with parenthesis. Using square brackets, you create a list to hold objects in one variable, Tuples, like an arrays. See the differences below.

• Lists are mutable and Tuples are immutable.
• The list is more convenient for actions like insertion and deletion and Tuples items may be accessed using the tuple data type.
• In lists, the impacts of iterations are Time Consuming and in Tuples Iterations have the effect of making things go faster.
• Lists take up more memory and when compared to a list, a tuple uses less memory.
• There are numerous techniques built into lists and there are not many built-in methods in Tuple
• Changes and faults that are unexpected are more likely to occur in lists and difficult to take place in a tuple.
• Lists consume a lot of memory of a system given the nature of this data structure but tuples consume less memory as compared.

Syntax: 

mylist = [100, “Ekgurukul”, 50]

Syntax: mytuples = (100, “Ekgurukul”, 10)

Literals can be defined as a data which is given in a variable or constant.

Python supports the following literals:

String Literals : String literals are formed by enclosing text in the single or double quotes. For example, string literals are string values.

Example:

# in single quotes
singlequote = 'ekgurukul.com'
# in double quotes
doublequote = "ekgurukul.com"
# multi-line String
multiquote = '''A universal Portal
            For Education 
           ekgurukul.com'''
  
print(singlequote)
print(doublequote)
print(multiquote)

Output:

ekgurukul.com
ekgurukul.com
A universal Portal
      For Education
         ekgurukul.com

Numeric Literals: Python supports three types of numeric literals integer, float and complex.

Example:

# Integer literal  
myinteger = 158  
#Float Literal  
myfloat = 108.2   
#Complex Literal   
mycomplex = 9.17i  
print(myinteger)
print(myfloat)
print(mycomplex)

Output:

158
108.2
9.17i

Boolean Literals : Boolean literals are used to denote Boolean values. It contains either True or False.

Example:

istrue_value =(1 == True)
isfalse_value = (1 == False)
res = True + 3
sum = False + 7
  
print("istrue_value is", istrue_value)
print("isfalse_value is", isfalse_value)
print("res:", res)
print("sum:", sum)

Output:

istrue_value is True
isfalse_value is False
res: 4
sum: 7

Some Special literals : Python contains one special literal, that is, 'None'. This special literal is used for defining a null variable. If 'None' is compared with anything else other than a 'None', it will return false.

Example:

thisisnone= None
print(thisisnone)

Output: 

None

A function is a block of self-contained statements which has a valid name, parameters list, and body. A function is a section of the program or a block of code that is written once and can be executed whenever required in the program. 

Functions make programming more functional and modular to perform modular tasks. Python provides several built-in functions to complete tasks and also allows a user to create new functions as well.

There are three types of functions:

• User-defined Functions: Functions which are defined by a user known as user-defined functions.
• Built-In Functions: copy(), len(), count() are the some built-in functions.
• Anonymous functions: These functions are also known as lambda functions because they are not declared with the standard def keyword.

Example: A general syntax of user defined function is given below.

def function_name(parameters list):  
    #--- statements---  
    return your_value  

Functions in Python refer to blocks that have organized, and reusable codes to perform single, and related events. Functions are important to create better modularity for applications that reuse a high degree of coding. Python has a number of built-in functions like print(). However, it also allows you to create user-defined functions.

Lists in Python > Lists in python can contain elements of different data types i.e., data type of lists can be heterogeneous. It has the disadvantage of consuming large memory.

Arrays in Python > Arrays in python can only contain elements of same data types i.e., data type of array should be types and it consumes far less memory than lists.

import array
a_1 = array.array('i', [11, 12, 13])
for i in a_1:
    print(i, end=' ')    
a_2 = array.array('i', [101, 102, 'string'])    
a_3 = [1, 2, 'string']
for i in a_3:
   print(i, end=' ')    

OUTPUT: 1 2 3
OUTPUT: TypeError: an integer is required (got type str)
#OUTPUT: 1 2 string

Numbers: Consists of integers, floating-point numbers, and complex numbers.

Example : 5, 9, 2.6,  

List: We have already seen a bit about lists, to put a formal definition a list is an ordered sequence of items that are mutable, also the elements inside lists can belong to different data types.

Example: list = [8478, "A Universal Portal for Education", 40]

Tuples:  This too is an ordered sequence of elements but unlike lists tuples are immutable meaning it cannot be changed once declared.

Example: my_tuples_is = (84, "A Universal Portal for Education", 25) 

String:  This is called the sequence of characters declared within single or double quotes.

Example:  "Hi, A Universal Portal for Education" or 'Hi, A Universal Portal for Education'

Sets: Sets are basically collections of unique items where order is not uniform.

Example: set = {101,102,103}

Dictionary: A dictionary always stores values in key and value pairs where each value can be accessed by its particular key.

Example: my_dictionary= {1: 'Fruits, 2:Games, 3:Education'} 

Boolean: There are only two boolean values: True and False

In Python, a namespace is a system that assigns a unique name to each and every object. A variable or a method might be considered an object. Python has its own namespace, which is kept in the form of a Python dictionary.

The namespace is a fundamental idea to structure and organize the code that is more useful in large projects. However, it could be a bit difficult concept to grasp if you're new to programming. Hence, we tried to make namespaces just a little easier to understand.

You may already be aware that everything in Python is an object, including strings, lists, functions, and so on. Another notable thing is that Python uses dictionaries to implement namespaces. A name-to-object mapping exists, with the names serving as keys and the objects serving as values. The same name can be used by many namespaces, each mapping it to a distinct object. Here are a few namespace examples:

Local Namespace: 

This namespace stores the local names of functions. This namespace is created when a function is invoked and only lives till the function returns.

Global Namespace: 

Names from various imported modules that you are utilizing in a project are stored in this namespace. It’s formed when the module is added to the project and lasts till the script is completed.

Built-in Namespace: 

This namespace contains the names of built-in functions and exceptions.

An interpreted language is any programming language which is not in machine-level code before runtime. Therefore, Python is an interpreted language.

A namespace in python refers to the name which is assigned to each object in python. The objects are variables and functions. As each object is created, its name along with space(the address of the outer function in which the object is), gets created. The namespaces are maintained in python like a dictionary where the key is the namespace and value is the address of the object. There 4 types of namespace in python-

1. Built-in namespace– These namespaces contain all the built-in objects in python and are available whenever python is running.
2. Global namespace– These are namespaces for all the objects created at the level of the main program.
3. Enclosing namespaces– These namespaces are at the higher level or outer function.
4. Local namespaces– These namespaces are at the local or inner function.

The common built-in data types in python are-

Numbers– They include integers, floating-point numbers, and complex numbers. eg. 1, 7.9,3+4i

List– An ordered sequence of items is called a list. The elements of a list may belong to different data types. Eg. [5,’market’,2.4]

Tuple– It is also an ordered sequence of elements. Unlike lists , tuples are immutable, which means they can’t be changed. Eg. (3,’tool’,1)

String– A sequence of characters is called a string. They are declared within single or double-quotes. Eg. “Sana”, ‘She is going to the market’, etc.

Set– Sets are a collection of unique items that are not in order. Eg. {7,6,8}

Dictionary– A dictionary stores values in key and value pairs where each value can be accessed through its key. The order of items is not important. Eg. {1:’apple’,2:’mango}

Boolean– There are 2 boolean values- True and False.