在 Python 中建立例項物件
要建立類的例項,使用類名呼叫類並傳遞其 __init__ 方法接受的任何引數。
"This would create first object of Employee class"
emp1 = Employee("Zara", 2000)
"This would create second object of Employee class"
emp2 = Employee("Manni", 5000)使用點號 (.) 運算子和物件來訪問物件的屬性。使用類名如下訪問類變數 −
emp1.displayEmployee() emp2.displayEmployee() print "Total Employee %d" % Employee.empCount
示例
現在,將所有概念放在一起 −
#!/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
輸出
當執行上述程式碼時,會產生以下結果 −
Name : Zara ,Salary: 2000 Name : Manni ,Salary: 5000 Total Employee 2
你可以隨時新增、刪除或修改類和物件的屬性 −
emp1.age = 7 # Add an 'age' attribute. emp1.age = 8 # Modify 'age' attribute. del emp1.age # Delete 'age' attribute.
使用以下函式代替普通語句來訪問屬性 −
- getattr(obj, name[, default]) − 訪問物件的屬性。
- hasattr(obj,name) − 檢查屬性是否存在。
- setattr(obj,name,value) − 設定屬性。如果屬性不存在,則會建立它。
- delattr(obj, name) − 刪除屬性。
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'
瞭解有關 Python 面向物件特性的更多資訊: Python 類和物件教程
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