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PORestrict creation/setting of an attribute
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copied!<p>How to restrict the creation of an attribute, outside its class/sub-class?</p> <pre><code>__all__ = ["Employee","Salary","Wage"] ################################################################################################## class Person(object): def __init__(self,fname,lname,gender): self.__setfname(fname) # "We are all adults." vs. "Name mangling." self.__setlname(lname) self.__setgender(gender) def __setfname(self,fname): self.__fname = fname def __setlname(self,lname): self.__lname = lname def __setgender(self,gender): self.__gender = gender def getname(self): return "{} {}".format(self.__fname,self.__lname) def getformattedname(self): if(self.__gender.lower() == "m"): return "Mr. {}".format(self.getname()) if(self.__gender.lower() == "f"): return "Ms. {}".format(self.getname()) if(self.__gender.lower() == ""): return "{}".format(self.getname()) class Payment(object): def __init__(self,amount,currency="INR"): # currency="USD" self.__setamount(amount) self.__setcurrency(currency) def __setamount(self,amount): self.__amount = amount def __setcurrency(self,currency): self.__currency = currency def getamount(self): return "{}".format(self.__amount) def getformattedamount(self): return "{} {}".format(self.getamount(),self.__currency) ################################################################################################## ################################################################################################## class Employee(Person): def __init__(self,fname,lname,gender): super(Employee,self).__init__(fname,lname,gender) def __str__(self): return self.getformattedname() class Salary(Payment): def __init__(self,amount,currency="INR"): super(Salary,self).__init__(amount,currency) def __str__(self): return self.getformattedamount() class Wage(Payment): def __init__(self,amount,currency="INR"): super(Wage,self).__init__(amount,currency) def __str__(self): return self.getformattedamount() ################################################################################################## </code></pre> <hr> <p>I'm OK with this:</p> <pre><code>e1._Person__fname = "Spam" s1._Payment__amount = "1000000000000000" </code></pre> <p>but the following code creates new attributes:</p> <pre><code>e1.fname = "New" s1.amount = -10 </code></pre> <hr> <pre><code>import re from com.example.model import Employee,Salary,Wage def printzip(l1,l2): print(list(zip([str(e) for e in l1],[str(e) for e in l2]))) (e1,e2) = (Employee("Sandeep","Mehta","m"),Employee("Varsha","Mehta","f")) (s1,s2) = (Salary(3000,"USD"),Salary(3000,"USD")) printzip([e1,e2],[s1,s2]) e1.fname = "New" s1.amount = -3000 e1._Person__fname = "Spam" s1._Payment__amount = "3000000000000000" for e in enumerate([e for e in dir(e1) if not (re.search(r"^__.*__$",e))]): print(e) for e in enumerate([e for e in dir(s1) if not (re.search(r"^__.*__$",e))]): print(e) printzip([e1],[s1]) </code></pre> <p><img src="https://i.stack.imgur.com/6496W.jpg" alt="Python IDLE"></p>

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