title: AttributeError 'int' object has no attribute isdigit in ipython in ubuntu
body: <pre><code>def input_base():
      print('please enter the number')
      base = input("Number : ")
      while not base.isdigit():
         print("It`s not integer")
         base = input("R.Number : ")
      return base 
      ...
  </code></pre>
  
  <p>This is my code and the error is:</p>
  
  <blockquote>
    <p>AttributeError : 'int' object has no attribute 'isdigit'</p>
  </blockquote>
  
  <p>I don't know how I could fix this code. I think, I should install some application, such a <code>python-numpy</code>, inside Ubuntu...<br>
  Is that right?</p>