Python @classmethod and @staticmethod

if you know C/C++, similarly, for Python, @classmethod works as the overloading, while @staticmethod works as encapsulation.

let me use some codes:

class Day:
    def __init__(self,day):
        self.day = day

    @classmethod
    def NewDay(cls,sday):
        return cls(int(sday))

    @staticmethod
    def getday(day):
        return day

    def getday(self):           # where hasattr works
        return self.day


mday = Day(20)
nday = Day.NewDay('30')
print(hasattr(mday,'getday'))   # True
print(hasattr(nday,'getday'))   # True
print(mday.day)                 # 20
print(nday.day)                 # 30
print(Day.getday(20))           # 20
  

the wrapped getday by @staticmethod is just the regular function that we want it to be inside class Day to fulfill integration and encapsulation.

another getday wrapped by @classmethod works as overloading, now it can work both on str and int.