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POChecking of instance fails using common tests for existence
 

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    <p>The following topics have been checked in lieu of my problem below.</p> <p><a href="https://stackoverflow.com/questions/6557349/in-python-how-do-i-check-if-an-instance-of-my-class-exists">In Python, how do I check if an instance of my class exists?</a></p> <p><a href="https://stackoverflow.com/questions/14549405/python-check-instances-of-classes">Python check instances of classes</a></p> <p>Bear with me as I am an absolute beginner in Python. I've just started tackling Classes and I decided that a simple family financials emulator is a good starting point for me. Below is my code:</p> <pre><code>class Family(object): def __init__(self,name,role,pay,allowance): self.name = name self.role = role self.pay = pay self.allowance = allowance def describe(self): print self.name + " is the " + self.role + " of the family. He brings home " + str(self.pay) + " in wages and has a personal allowance of " + str(self.allowance) + "." class Parent(Family): def gotRaise(self,percent): self.pay = self.pay * int(1 + percent) print self.name + " received a pay increase of " + str((100*percent)) + ("%. His new salary is ") + str(self.pay) + "." def giveAllowance(self,val,target): if hasattr(target, Family): self.pay = self.pay - int(val) target.pay = target.pay + int(val) print self.name + " gave " + target.name + " an allowance of " + str(val) + "." + target.name + "'s new allowance is " + str(target.allowance) + "." else: print "" class Child(Family): def stealAllowance(self,val,target): self.allowance = self.allowance + int(val) target.allowance = target.allowance - int(val) def spendAllowance(self,val): self.allowance = self.allowance - int(val) monty = Parent("Monty","Dad",28000,2000) monty.describe() # 'Monty is the Dad of the family. He brings home 28000 in wages and has a personal allowance of 2000.' monty.giveAllowance(1000,jane) # Produces a "NameError: name 'jane' is not defined" error. </code></pre> <p>The point of issue is the giveAllowance() function. I have been trying to find a way to check if the target instance of Family exists and to return a transfer of value if it does and a normal string if it doesn't. However, hasattr(), try - except NameError, isinstance(), and even vars()[target] all fail to address the NameError above.</p> <p>Am I missing something here that I should be doing with respect to classes, ie. an exception when checking for instances from inside another class, wrong syntax, etc? If at all possible, I want to keep away from dictionaries unless they are the last resort, as it seems that from one of the links above, it's the only way. </p> <p>Thanks!</p>
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