Class
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class Employee:
raise_percent = 1.05 # class variable
num_emp = 0 # keep the number of employees
def __init__(self, name, last, age, pay):
self.name = name # instance variable
self.last = last
self.age = age
self.pay = pay
Employee.num_emp += 1
def fullname(self):
print(f"{self.name} {self.last}")
def apply_raise(self):
self.pay = self.pay * self.raise_percent
## or
# self.pay = self.pay * Employee.raise_percent # !!
@classmethod
def set_raise(cls, amount):
cls.raise_percent = amount
@classmethod
def from_string(cls, emp_str):
name, last, age, pay = emp_str.split('-')
return cls(name, last, int(age), float(pay))
@staticmethod
def holiday_print(day):
if day == 'weekend':
print('This is an off day')
else:
print('This is not an off day')
emp_1 = Employee("James", "Hughes", "32", 5000)
emp_2 = Employee("Charlie", "Brown", "22", 3000)
emp_1.apply_raise()
print(emp_1.__dict__) # {'name':'James', ...}
emp_1.experience = 10 # it only adds this instance not the remaining instance of the class
Employee.raise_percent = 1.06 # class uzerinden guncelledigimiz icin diger instancelari da guncellenir
emp_1.raise_percent = 1.07 # bu guncellemiyor aksine emp_1.experienceteki gibi yeni bir sey yaratacak
Employee.set_raise(1.06) # instance uzerinden de yapilabilirdik
emp_1 = Employee.from_string('James-Hughes-32-5000')
emp_1.holiday_print('working day')
Class variable vs. Instance variable
-
Instance variable: Classtan yaratilan objelerin kendilerine ozgu degiskenleri
-
Class variable: Classtan yaratilan tum objelerde paylasilan degiskenler
Class method vs. Static method
@classmethoddecorator methods take class instead of an instance as the first argument
__new__
- It is called when a class is instantiated.
- It is similar to
__init__ - It is a static method.
- Precedence
__new__>__init__
from collections import namedtuple
Node = namedtuple('Node', 'val left right')
Node.__new__.__defaults__ = (Node,) * len(Node._fields)
Node() # Node(val=None, left=None, right=None)