title: Instance vs. Member Variables python 3
body: <p>What is the difference between instance and member variables in python 3 and how would you create them?
  We are just learning how to create classes in python 3 and I do not understand these variable types.</p>
  
  <p>Can I set them before the "__ init __ " method?</p>
  
  <p>I am writing a code where ID needs to be an instance variable and balance and annualInterestRate need to be member variables. This is what I have for that:</p>
  
  <pre><code>    def __init__(self, ID=0, initialbalance=100.0, annualInterestRate=0.0):
          self.__ID = int(ID)
          self.__balance = float(initialbalance)
          self.__annualInterestRate = float(annualInterestRate)
  </code></pre>
  
  <p>To make Id a class variable, should I set it to the amount before "__ init __"? I do need to be able to change the value later in the program.</p>