Python

1. Python Python is one of the most popular programming languages. Although it is a general-purpose language, it is used in various areas of applications such as Machine Learning, Artificial Intelligence, web development, IoT, and more. This Python tutorial has been written for the beginners to help them understand the basic to advanced concepts of Python Programming Language. After completing this tutorial, you will find yourself at a great level of expertise in Python, from where you can take yourself to the next levels to become a world class Software Engineer. Python is a very popular general-purpose interpreted, interactive, object-oriented, and high-level programming language. Python is dynamically-typed and garbage-collected programming language. It was created by Guido van Rossum during 1985- 1990. Like Perl, Python source code is also available under the GNU General Public License (GPL).

2. Why to Learn Python? • Python is consistently rated as one of the world's most popular programming languages. Python is fairly easy to learn, so if you are starting to learn any programming language then Python could be your great choice. Today various Schools, Colleges and Universities are teaching Python as their primary programming language. There are many other good reasons which makes Python as the top choice of any programmer: • Python is Open Source which means its available free of cost. • Python is simple and so easy to learn • Python is versatile and can be used to create many different things. • Python has powerful development libraries include AI, ML etc. • Python is much in demand and ensures high salary

3. Python - Functions A Python function is a block of organized, reusable code that is used to perform a single, related action. Functions provide better modularity for your application and a high degree of code reusing. A top-to-down approach towards building the processing logic involves defining blocks of independent reusable functions. A Python function may be invoked from any other function by passing required data (called parameters or arguments). The called function returns its result back to the calling environment.

4. Types of Python Functions • Python provides the following types of functions − • Built-in functions • Functions defined in built-in modules • User-defined functions • Python's standard library includes number of built-in functions. Some of Python's built-in functions are print(), int(), len(), sum(), etc. These functions are always available, as they are loaded into computer's memory as soon as you start Python interpreter. • The standard library also bundles a number of modules. Each module defines a group of functions. These functions are not readily available. You need to import them into the memory from their respective modules. • In addition to the built-in functions and functions in the built-in modules, you can also create your own functions. These functions are called user-defined functions.

5. Defining a Function in Python You can define custom functions to provide the required functionality. Here are simple rules to define a function in Python. Function blocks begin with the keyword def followed by the function name and parentheses ( ( ) ). Any input parameters or arguments should be placed within these parentheses. You can also define parameters inside these parentheses. The first statement of a function can be an optional statement; the documentation string of the function or docstring. The code block within every function starts with a colon (:) and is indented. The statement return [expression] exits a function, optionally passing back an expression to the caller. A return statement with no arguments is the same as return None.