__init__.py , among other things, labels a directory as a python directory and lets you set variables on a package wide level. __main__.py , among other things, is run if you try to run a compressed group of python files. __main__.py allows you to execute packages.
The __name__ == "__main__" runs blocks of code only when our Python script is being executed directly from a user. This is powerful as it allows our code to have different behavior when it's being executed as a program instead of being imported as a module.
'__main__' is the name of the scope in which top-level code executes. A module's __name__ is set equal to '__main__' when read from standard input, a script, or from an interactive prompt.
The __init__ method lets the class initialize the object's attributes and serves no other purpose. It is only used within classes.
When a python program is executed, python interpreter starts executing code inside it. It also sets few implicit variable values, one of them is __name__ whose value is set as __main__ . For python main function, we have to define a function and then use if __name__ == '__main__' condition to execute this function.
__init__.py , among other things, labels a directory as a python directory and lets you set variables on a package wide level. __main__.py , among other things, is run if you try to run a compressed group of python files. __main__.py allows you to execute packages.
What is Main Function in Python. In most programming languages, there is a special function which is executed automatically every time the program is run. This is nothing but the main function, or main() as it is usually denoted. It essentially serves as a starting point for the execution of a program.
The python __init__ method is declared within a class and is used to initialize the attributes of an object as soon as the object is formed. While giving the definition for an __init__(self) method, a default parameter, named 'self' is always passed in its argument. This self represents the object of the class itself.
Starting with Python 3.3, Implicit Namespace Packages were introduced. These allow for the creation of a package without any __init__.py file. Of course, it can still be present if package initialization is needed. But it is no longer required.
"__init__" is a reserved method in python classes. It is known as a constructor in OOP concepts. This method called when an object is created from the class and it allows the class to initialize the attributes of a class.
Advantages : Every Python module has it's __name__ defined and if this is '__main__', it implies that the module is being run standalone by the user and we can do corresponding appropriate actions. If you import this script as a module in another script, the __name__ is set to the name of the script/module.
The most basic and easy way to run a Python script is by using the python command. You need to open a command line and type the word python followed by the path to your script file like this: python first_script.py Hello World! Then you hit the ENTER button from the keyboard, and that's it.
If you have your own python files you want to import, you can use the import statement as follows: >>> import my_file # assuming you have the file, my_file.py in the current directory. # For files in other directories, provide path to that file, absolute or relative.
Scripts are runnable Python programs that do something when executed. Modules are Python files that are intended to be imported into scripts and other modules so that their defined members—like classes and functions—can be used.
The magic functions are for the customization of the lifespan of the objects that are created from the type that they've been implemented. __init__ runs right after the object is created. initialize in your example however is just a method of the object.
In Python, there is no existence of Private methods that cannot be accessed except inside a class. However, to define a private method prefix the member name with the double underscore “__”. Note: The __init__ method is a constructor and runs as soon as an object of a class is instantiated.
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Note: The __init__() function is called automatically every time the class is being used to create a new object.
Lambda functions are similar to user-defined functions but without a name. They're commonly referred to as anonymous functions. Lambda functions are efficient whenever you want to create a function that will only contain simple expressions – that is, expressions that are usually a single line of a statement.
The primary difference between tuples and lists is that tuples are immutable as opposed to lists which are mutable. Therefore, it is possible to change a list but not a tuple. The contents of a tuple cannot change once they have been created in Python due to the immutability of tuples.
Lists and arrays both are mutable and store ordered items. List can store elements of different types, but arrays can store elements only of the same type. List provides more flexibility as it doesn't require explicit looping, but arrays require explicit looping to print elements.
Python Tutor is a free online learning website that offers tutorial classes to learn the basics of programming. It provides you with a way to see how your Python code works. You can use it to complement other learn Python tutorials resources as it gives you insight into debugging your Python code.
__name__ (A Special variable) in Python
__name__ is one such special variable. If the source file is executed as the main program, the interpreter sets the __name__ variable to have a value “__main__”. If this file is being imported from another module, __name__ will be set to the module's name.
Unlike main(), the init() function is optional but can occur multiple times in a package; on the other hand, every program must have a single main() function in the main package. Now, change the order of the init() function and compile and execute the same code. Run the code sample to see how the output changes.
The __file__ special variable is an attribute of a Python module that contains the path of the script or module from which it is accessed. It is naturally set by the interpreter when a Python script is executed or imported.