modules name. Polymorphism in Python(with Examples) - Programiz With the help of main() function in Python, we can execute a ton of functionalities as and when needed, and also control the flow of execution. In this case, you took advantage of reusing your code instead of defining all of the logic in main(). More on main() - http://ibiblio.org/g2swap/byteofpython/read/module-name.html. The idea is to put some commonly or repeatedly done tasks together and make a function so that instead of writing the same code again and again for different inputs, we can do the function calls to reuse code contained in it over and over again. In Python a function is defined using the def keyword: Example Get your own Python Server def my_function (): print("Hello from a function") Calling a Function To call a function, use the function name followed by parenthesis: Example Get your own Python Server def my_function (): print("Hello from a function") my_function () Try it Yourself A-143, 9th Floor, Sovereign Corporate Tower, We use cookies to ensure you have the best browsing experience on our website. The use of docstring in functions is optional but it is considered a good practice. What are Lambda Functions and How to Use Them? Please tell me how main method works in python ? In the above example, Ive defined a function called get_got, which returns the string stored in the variable data. However, the interpreter of the Python programming language executes each of the lines serial-wise from the top of the file and has no explicit main () function. behavior - dancing, singing, etc. On Linux or macOS, the name of the Python 3 executable is python3, so you should run Python scripts by typing python3 script_name.py after the $. You can invoke it with python -m venv [directory]. __name__ will be equal to: Now youre ready to go write some awesome Python main() function code! In short, __name__ variable helps you to check if the file is being run directly or if it has been imported. News difficulty : Medium. Inside the conditional block, you have added four lines of code (lines 12, 13, 14, and 15): Now, run your best_practices.py script from the command line to see how the output will change: First, the output shows the result of the print() call outside of process_data(). Use the different values of __name__ to determine the context and change the behavior of your code with a conditional statement. You can read more about defining strings in Basic Data Types in Python. And as I said before, the value of this string depends on how the code is being executed. A main function is used so the file can be imported into a REPL without running as a script, this is what the if statement does. The syntax for the return statement is: The return statement can consist of a variable, an expression, or a constant which is returned at the end of the function execution. This can be achieved using the name attribute of the module. Python Built-in Functions - Javatpoint rev2023.4.21.43403. Go produce the performance tree, by default, computer trusted on the library lxml. Ltd. All rights Reserved. As a result, a module can discover whether or not it is running in the import systems reference for details on how this works. Functions in Python - Tutorial Gateway Scrapy Tutorial: How To Make A Web-Crawler Using Scrapy? There are two primary ways that you can instruct the Python interpreter to execute or use code: You can read a lot more about these approaches in How to Run Your Python Scripts. its __name__ is set to the string '__main__'. Python Functions : A Complete Beginners Guide, Learn How To Use Map Function In Python With Examples, Python time sleep() One Stop Solution for time.sleep() Method, How To Sort A Dictionary In Python : Sort By Keys , Sort By Values, String Function In Python: How To Use It with Examples, How To Convert Decimal To Binary In Python, Python Tuple With Example: Everything You Need To Know, How to Reverse a List in Python: Learn Python List Reverse() Method, Learn What is Range in Python With Examples, Everything You Need To Know About Hash In Python. contains a collection of tutorials and references on how to distribute and Does Python have a string 'contains' substring method? top-level environment. When echo.py is imported, the Now, the main function is like any other function in Python. running top-level code meant for script use which is put in the What were the most popular text editors for MS-DOS in the 1980s? However, Python interpreter runs the code right from the first line. 2. And on execution, it prints Hello, World!. Python3 def fun (): Nevertheless, having a defined starting point for the execution of a program is useful for understanding how a program works. Limiting the number of "Instance on Points" in the Viewport. I have assimilated the output of the code and written it down below for your easy reference: Note: If you run this code as a script or if you import it, the output is going to be the same. This is because the __name__ variable had the value "best_practices", so Python did not execute the code inside the block, including process_data(), because the conditional statement evaluated to False. Get tips for asking good questions and get answers to common questions in our support portal. ", "The variable __name__ tells me which context this file is running in.". How to Install OpenCV for Python on Windows? You also know why and when a main() function is used. Given an array A of size N of integers. So lets understand what exactly is the main function in Python.
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