title: How to verify input in UITextField (i.e., numeric input)
body: <p>I am fairly new to iPhone development and I have what seems to be a simple question that I cannont figure out.  How can I verify that a user input a number and a decimal into the text field? </p>
  
  <p>I have tried many different things but the closes I can get only allows for numeric strings of the form: 5.34 or 23.89.  I need it to allow numbers such as; 0.50 or 432.30, just something with a zero as the last input value.  I attempted to check the string input by converting it to a float and then back to a string, but get the abovementioned results.  </p>
  
  <p>ANY help would be great (same with sample code!)  THANKS!</p>