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How to Use Main Function in Python with Example

Students want to know how to use the main function in Python, here our experts will explain to you in detail with example.

What Is The Main Function in Python And How to Use Python Function?

Every programming languages have a main() work as a pre-defined technique to show to the compiler that it is the start of the execution stream. Python language is a special case to this, as its execution is in a sequential way. And the principal line of the code will be the beginning stage naturally.

Notwithstanding of main() function not being a required component. If the software engineer wishes to have a principle strategy to order different pieces of the code. Generally, make a client characterized technique, which will work like different strategies in python.

Check out this blog for complete pieces of information. Regarding what is the main function in python and how to use the Python function.

What is the Main Function in Python 

The main functions resemble the program entry point. However, Python translator runs the code directly from the principal line. The code execution begins from the beginning line and goes line by line. Also, it doesn’t make a difference where the main function is available or it is available or not. 

In Python since there are no main() functions. Also, when the command to run a program of Python is given to the translator. The code that is at level 0 space is to be executed.

In any case, before doing that, it will describe a couple of exceptional variables. Also, __name__ is one such uncommon variable. In the event that the source files are executed as the main program.

The translator sets the __name__ variable to have a value__main__. Also, in the event that this record is being imported from another module, __name__ will be introduced to the module’s name. 

Likewise, __name__ is a worked in variable which assesses to the name of the present module.

How to define Python Main Function?

The main process is determined in an alike fashion like different functions described in python.

Basic main function:

print(‘Introduction to main() function’)

def main():

print(“It is main function”)

print(‘Outside main function’)

Output: demo.py

>>>

=== RESTART: C:/Users/hp/AppData/Local/Programs/Python/Python37-32/demo.py ===

Introduction to main() function

Outside main function

>>>

Explanation:

Python interpreter begins the python execution file from the head. Firstly, it will print the primary print statement i.e Introduction to main() function. After that it discovers the main() process definition. Since it is is a small definition and not a function call. So it neglects this and performs the next print statement that follows this.

Note:  In python, it is not important the name ‘main’ method as main(). It can be determined with any actual identifier name like main(), main1(), etc.

Main() Execution needs a detailed knowledge of the __name__ variable.x

For Example

# Python program to demonstrate

# main() function

  print(“Hi”)

# Defining main function

def main():

    print(“Hello there”)

# Using the special variable 

# __name__

if __name__==”__main__”:

    main()

Output:

Hi

Hello there

When the above program is performed, the interpreter defines the primary name value as “main”. When the translator finds the if statement it checks the name value and when the value of “if” is correct. It runs the main function otherwise the main function is not completed.

Brief about __name__ variable:

Variable __name__ is a unique absolute variable that includes a string value and string, that will be depending on how the code executed.

Essentially there are two methods in which python translator execute code and __name__ value is populated by this.

1. The popular method for file executes as a python script

In this case, __name__ will include the string “__main__”

2. By carrying the required code from one file of python to different files.

In this case, __name__ will incorporate the imported module name

__name__ variable supports to verify if the file of python is being run immediately or if it has been introduced from some different file.

Main function as Module 

Subsequent to bringing the script of Python as a module the variable __name__ gets the deserving equivalent to the name of the imported python content.

For Example:

Let’s suppose there are two Files(File3.py and File4.py). File3 is as follows.

# File3.py 

print(“File3 __name__ = %s” %__name__)

if __name__ == “__main__”: 

    print(“File3 is being run directly”)

else: 

    print(“File3 is being imported”)

Output:

File1 __name__ = __main__

File1 is being run directly

Now, when the File3.py is imported into File4.py, the value of __name__ changes.

# File4.py 

import File3

print(“File4 __name__ = %s” %__name__)

if __name__ == “__main__”:

    print(“File4 is being run directly”)

else: 

    print(“File4 is being imported”)

Output:

File3 __name__ = File3

File3 is being imported

File4 __name__ = __main__

File4 is being run directly

As seen above, when File3.py is executed directly, the translator sets the variable  __name__ as __main__ and when it is executed by File4.py by sending, the variable __name__ is set as the python name script, i.e. File3.

Therefore, it can be assumed that if __name__ == “__main__” is the program part that executed when the script is run from the command line utilizing a command like Python File3.py.

Conclusion

To this end, this post has provided all the relevant information about what is the main function in Python and how to use the python function. This includes data on what the main functions are, ways to define them with useful examples.

Check all this information and use them as per your programming requirements. Basically, python’s main function is used as a pointer in a specific entry. Therefore, it is necessary to know the purpose of this main function.

It is not mandatory to utilize the main() function method in your python programming. And it totally depends on you whether you want to have it in the program or not. However, it is useful to use this function as it helps to execute a number of functionalities and the place where it is required, and it can handle the flow of your executed programming.

As a result, if you are facing any difficulty regarding python programming assignments and homework, then you can take our experts’ help for it, which is available at reasonable prices, and it will be delivered within the slotted time.

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