oop/static_methods.py - main - eb/python_learn

oop/static_methods.py
84 строки2 KB
EvgeniyBudaev
Статические методы - @staticmethod, @classmethod
15 фев 2021, 07:04
15 фев 2021, 07:049ceaf7e
class StaticTest:
  x = 1

t1 = StaticTest()
print('Via instance: ', t1.x) # 1
print('Via class: ', StaticTest.x) # 1
t1.x = 2 # создается атрибут на уровне инстанции
print('Via instance: ', t1.x) # 2
print('Via class: ', StaticTest.x) # 1

StaticTest.x = 3
print('Via instance: ', t1.x) # 2
print('Via class: ', StaticTest.x) # 3

# Статические методы
class Date:

  def __init__(self, month, day, year):
    self.month = month
    self.day = day
    self.year = year

  def display(self):
    return f"{self.month}-{self.day}-{self.year}"  

  @classmethod  
  def millenium_c(cls, month, day):
    return cls(month, day, 2000)  

  @staticmethod
  def millenium_s(month, day):
    return Date(month, day, 2000) 


d1 = Date.millenium_c(6, 9)
d2 = Date.millenium_s(6, 9) 

print(d1.display())
print(d2.display())

class DateTime(Date):
  def display(self):
    return f"{self.month}-{self.day}-{self.year} - 00:00:00PM"  


dt1 = DateTime(10, 10, 1990)
dt2 = DateTime.millenium_s(10, 10)
print(isinstance(dt1, DateTime)) # True. isinstance - проверяет тип инстанции 
print(isinstance(dt2, DateTime)) # False.
print(dt1.display()) # 10-10-1990 - 00:00:00PM
print(dt2.display()) # 10-10-2000

dt1 = DateTime(10, 10, 1990)
dt2 = DateTime.millenium_c(10, 10)
print(isinstance(dt1, DateTime)) # True
print(isinstance(dt2, DateTime)) # True
print(dt1.display()) # 10-10-1990 - 00:00:00PM
print(dt2.display()) # 10-10-2000 - 00:00:00PM

# ===
class StrConverter:

  @staticmethod
  def to_str(bytes_or_str):
    if isinstance(bytes_or_str, bytes):
      value = bytes_or_str.decode('utf-8')
    else:
      value = bytes_or_str
    return value 

  @staticmethod
  def to_bytes(bytes_or_str): 
    if isinstance(bytes_or_str, str):
      value = bytes_or_str.encode('utf-8')
    else:
      value = bytes_or_str
    return value 


print(StrConverter.to_str('\x41')) # A
print(StrConverter.to_str('A')) # A

print(StrConverter.to_bytes('\x41')) # b'A'
print(StrConverter.to_bytes('A')) # b'A'