在Python中创建实例对象

为了创建一个类的实例对象，你需要使用类名调用类，并传入其init方法接受的任何参数。

"This would create first object of Employee class"
emp1 = Employee("Zara", 2000)
"This would create second object of Employee class"
emp2 = Employee("Manni", 5000)

你可以使用点（.）操作符加上对象名称来访问对象的属性。类变量可以通过以下方式访问：

emp1.displayEmployee()
emp2.displayEmployee()
print "Total Employee %d" % Employee.empCount

示例

现在，将所有的概念放在一起−

#!/usr/bin/python
class Employee:
   'Common base class for all employees'
   empCount = 0
   def __init__(self, name, salary):
      self.name = name
      self.salary = salary
      Employee.empCount += 1
   def displayCount(self):
   print "Total Employee %d" % Employee.empCount
   def displayEmployee(self):
      print "Name : ", self.name, ", Salary: ", self.salary
"This would create first object of Employee class"
emp1 = Employee("Zara", 2000)
"This would create second object of Employee class"
emp2 = Employee("Manni", 5000)
emp1.displayEmployee()
emp2.displayEmployee()
print "Total Employee %d" % Employee.empCount

输出

当上述代码被执行时，产生以下结果 –

Name : Zara ,Salary: 2000
Name : Manni ,Salary: 5000
Total Employee 2

您可以随时添加、删除或修改类和对象的属性-

emp1.age = 7 # Add an 'age' attribute.
emp1.age = 8 # Modify 'age' attribute.
del emp1.age # Delete 'age' attribute.

不使用普通语句访问属性，而是可以使用以下函数：

• getattr(obj, name[, default]) – 访问对象的属性。
• hasattr(obj, name) – 检查属性是否存在。
• setattr(obj, name, value) – 设置属性。如果属性不存在，则创建。
• delattr(obj, name) – 删除属性。

hasattr(emp1, 'age') # Returns true if 'age' attribute exists
getattr(emp1, 'age') # Returns value of 'age' attribute
setattr(emp1, 'age', 8) # Set attribute 'age' at 8
delattr(empl, 'age') # Delete attribute 'age'

了解更多关于Python面向对象特性：Python 类与对象教程