If __name__ == '__main__':

Definition

The 'if __name__ == '__main__':' statement is a Python idiom used to control the execution of a script. It allows a script to be executed either as a standalone program or as a module imported by another program.

5 Must Know Facts For Your Next Test

1. The 'if __name__ == '__main__':' statement checks if the current Python script is being run as the main program, rather than being imported as a module.
2. This statement allows you to write code that should only be executed when the script is run directly, and not when it is imported as a module.
3. Code placed inside the 'if __name__ == '__main__':' block will only be executed when the script is run directly, and not when it is imported as a module.
4. This is useful for writing scripts that can be both imported as modules and executed as standalone programs.
5. The '__name__' variable is a built-in Python variable that contains the name of the current module. When a script is run directly, '__name__' is set to '__main__'.

Review Questions

• Explain the purpose of the 'if __name__ == '__main__':' statement in Python.
  • The 'if __name__ == '__main__':' statement in Python is used to control the execution of a script. It allows a script to be executed either as a standalone program or as a module imported by another program. When a script is run directly, the '__name__' variable is set to '__main__', and the code inside the 'if __name__ == '__main__':' block will be executed. However, when the script is imported as a module, the '__name__' variable will be set to the name of the module, and the code inside the 'if __name__ == '__main__':' block will not be executed. This is useful for writing scripts that can be both imported as modules and executed as standalone programs.
• Describe how the 'if __name__ == '__main__':' statement is used to differentiate between a script being run directly and a script being imported as a module.
  • The 'if __name__ == '__main__':' statement is used to differentiate between a script being run directly and a script being imported as a module. When a script is run directly, the '__name__' variable is set to '__main__', and the code inside the 'if __name__ == '__main__':' block will be executed. However, when the script is imported as a module, the '__name__' variable will be set to the name of the module, and the code inside the 'if __name__ == '__main__':' block will not be executed. This allows the script to be used both as a standalone program and as a module that can be imported and used by other programs.
• Analyze the benefits of using the 'if __name__ == '__main__':' statement in a Python script.
  • The 'if __name__ == '__main__':' statement in Python provides several benefits: 1. It allows a script to be used both as a standalone program and as a module that can be imported by other programs. 2. It prevents the execution of certain code when the script is imported as a module, which can be useful for avoiding unintended side effects or unnecessary computations. 3. It enables the script to have a 'main' function or block of code that is only executed when the script is run directly, making the script more modular and reusable. 4. It makes the script more flexible and easier to maintain, as the 'if __name__ == '__main__':' statement separates the script's execution logic from its functionality as a module.

Related terms

Module:

A module in Python is a file containing Python definitions and statements. Modules can be imported and used by other Python programs.

Executable Script: An executable script is a Python file that can be run directly from the command line, like a standalone program.

Imported Module: When a Python module is imported by another program, it can be used to provide functionality, data, or other resources to the importing program.