title: Android CharSequence Number Detection(0-9) in one statement without using if else
body: <p>I am new in android and trying to make a calculator...</p>
  
  <p>Now i have extracted whole expression in a charSequence variable.</p>
  
  <p>e.g 30+69-(3-10)</p>
  
  <p>Now i need to detect whether the first character of charSequence variable is either a number (0-9) or a character/operator.</p>
  
  <p>i can use get.subSequence(0,1) but dont want to compare it with every number to decide whether its a number or not and if its a number then which one it is....</p>
  
  <p>How can i compare it with every number using fewer conditions and also extract that specific number....</p>