Variable in Python | ** Operator in Python | NameError in Python | int and float in Python |

With Python, it is possible to use the ** operator to calculate powers print(5 ** 2) print(5 * 5) print(2 ** 7) The equal sign (=) is used to assign a value to a variable. Afterwards, no result is displayed before the next interactive prompt: width = 20 height = 5 * 9 print(width * height) If a variable is not “defined” (assigned a value), trying to use it will give you an error: print(n) # try to access an undefined variable Traceback (most recent call last): File "stdin", line 1, in module NameError: name 'n' is not defined In interactive mode, the last printed expression is assigned to the variable _. This means that when you are using Python as a desk calculator, it is somewhat easier to continue calculations, for example: tax = 12.5 / 100 price = 100.50 tax_on_current_price = tax * price answer = price + tax_on_current_price print(answer) Variable Names A variable can have a short name (like x and y) or a more descriptive name (age, carname, total_volume). Rules for Python variables: A variable name must start with a letter or the underscore character A variable name cannot start with a number A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ ) Variable names are case-sensitive (age, Age and AGE are three different variables) A variable name cannot be any of the Python keywords. name = "devvrat" #True my_name = "devvrat" #True 1name = "devvrat" #False name1 = "devvrat" #True name@ = "devvrat" #false Camel Case myName = "devvrat" Pascal Case MyName = "devvrat" Snake Case my_name = "devvrat" Python is a cross-platform programming language, which means that it can run on multiple platforms like Windows, macOS, Linux, and has even been ported to the Java and .NET virtual machines. It is free and open-source. Let's create a very simple program called Hello World. A "Hello, World!" is a simple program that outputs Hello, World! on the screen. Since it's a very simple program, it's often used to introduce a new programming language to beginners. Type the following code in any text editor or an IDE and save it as hello_world.py Python is an easy to learn, powerful programming language. It has efficient high-level data structures and a simple but effective approach to object-oriented programming. Python’s elegant syntax and dynamic typing, together with its interpreted nature, make it an ideal language for scripting and rapid application development in many areas on most platforms. The Python interpreter and the extensive standard library are freely available in source or binary form for all major platforms from the Python web site, https://www.python.org/, and may be freely distributed. The same site also contains distributions of and pointers to many free third party Python modules, programs and tools, and additional documentation. The Python interpreter is easily extended with new functions and data types implemented in C or C++ (or other languages callable from C). Python is also suitable as an extension language for customizable applications. Be More Productive Save time while PyCharm takes care of the routine. Focus on the bigger things and embrace the keyboard-centric approach to get the most of PyCharm's many productivity features. Get Smart Assistance PyCharm knows everything about your code. Rely on it for intelligent code completion, on-the-fly error checking and quick-fixes, easy project navigation, and much more. Boost Code Quality Write neat and maintainable code while the IDE helps you keep control of the quality with PEP8 checks, testing assistance, smart refactorings, and a host of inspections. Simply All You Need PyCharm is designed by programmers, for programmers, to provide all the tools you need for productive Python development. Intelligent Python Assistance PyCharm provides smart code completion, code inspections, on-the-fly error highlighting and quick-fixes, along with automated code refactorings and rich navigation capabilities. Web Development Frameworks PyCharm offers great framework-specific support for modern web development frameworks such as Django, Flask, Google App Engine, Pyramid, and web2py. Scientific Tools PyCharm integrates with IPython Notebook, has an interactive Python console, and supports Anaconda as well as multiple scientific packages including matplotlib and NumPy. Cross-technology Development In addition to Python, PyCharm supports JavaScript, CoffeeScript, TypeScript, Cython, SQL, HTML/CSS, template languages, AngularJS, Node.js, and more. Even though most of today's Linux and Mac have Python pre-installed in it, the version might be out-of-date. So, it is always a good idea to install the most current version. The Easiest Way to Run Python The easiest way to run Python is by using PyCharm.