PYTHON

python if main

# if __name__ == '__main__' checks if a file is imported as a module or not.
# example: 
def main():
    print('Hello World')
    
if __name__ == '__main__':
    # This code won't run if this file is imported.
    main()

if main python

# Python program to execute
# main directly
print ("Always executed")
 
if __name__ == "__main__":
    print ("Executed when invoked directly")
else:
    print ("Executed when imported")