title: In ruby , How do you check if an input is a float or a string ?
body: <p>I am asking the user to enter a number ( Price for something).
  How do I proceed with the code if it is a number. </p>
  
  <p>If the input is not a valid number, then I want to display an error code saying " please input a numerical value"</p>
  
  <p>Similarly, how do I check if it is a string. the user has to choose from 5 letters, A-E. If they input anything other than a string, I want to display an error message.  I haven't learnt how to create groups of values in a variable, example ,</p>
  
  <p>letters = {A,B,C,D,E}. 
  ideally, I would like to search through letters, and if it is not something that the user inputed, then i want to print an error message. </p>
  
  <p>However, I have only learned up to conditional statements so far. I don't want there to be loops. </p>