Static Methods and Class Methods
  • Instance Methods: The most common method type. Able to access data and properties unique to each instance.
  • Static Methods: Cannot access anything else in the class. Totally self-contained code.
  • Class Methods: Can access limited methods in the class. Can modify class specific details.
    1. class Vehicle(object):
    2.     """Document String: Define a Vehicle class"""
    3.  
    4.     count = 0; # static variable
    5.  
    6.     def info():
    7.         return Vehicle.count;
    8.  
    9.     info = staticmethod(info) # static function
    10.  
    11.     def __init__(self, brand, year):
    12.         self._brand = brand;
    13. 	self._year = year;
    14.         Vehicle.count += 1;
    15.  
    16.     def __str__(self):
    17.         return self._brand+' '+str(self._year)
    18.  
    19.     def __del__(self):
    20.         Vehicle.count -= 1;
    21.  
    22. def main():
    23.     vehicles = [Vehicle("Buick", 1998), Vehicle("Lincoln", 1999)]
    24.  
    25.     print(Vehicle.info())
    26.     print(vehicles[1].info())
    27.  
    28. if __name__ == '__main__':
    29.     main()
    30. 		
    1. class Vehicle(object):
    2.     """Document String: Define a Vehicle class"""
    3.  
    4.     count = 0;
    5.  
    6.     @staticmethod
    7.     def info():
    8.         return Vehicle.count;
    9.  
    10.     @classmethod
    11.     def cla(cls):
    12.         print('Call class method ...')
    13.         print(Vehicle.info()) # class methods can call static methods
    14.  
    15.     def __init__(self, brand, year):
    16.         self._brand = brand;
    17. 	self._year = year;
    18.         Vehicle.count += 1;
    19.  
    20.     def __str__(self):
    21.         return self._brand+' '+str(self._year)
    22.  
    23.     def __del__(self):
    24.         Vehicle.count -= 1;
    25.  
    26. def main():
    27.     vehicles = [Vehicle("Buick", 1998), Vehicle("Lincoln", 1999)]
    28.  
    29.     print(Vehicle.info()) # call static method
    30.     print(vehicles[1].info())
    31.  
    32.     Vehicle.cla() # call class method
    33.  
    34. if __name__ == '__main__':
    35.     main()
    36.
    Reference
  • Instance vs. Static vs. Class Methods in Python: The Important Differences