Regular Expressions Hints .....

     abc…     Letters
      123…     Digits
      \d     any Digit
      .     any Character
      \.     Period
      [abc]     Only a, b, or c
      [^abc]     Not a, b, nor c
      [a-z]     Characters a to z
      [0-9]     Numbers 0 to 9
      {m}     m Repetitions
      {m,n}     m to n Repetitions
      *     Zero or more repetitions
      +     One or more repetitions
      ?     Optional
      \s     any Whitespace
      ^…$     Starts and ends
      ()     capture Group
      (a(bc))     capture Sub group
      (.*)     capture Variable content
      (a|b)     Matchs a or b
      \w     any Alphanumeric character
      \W     any Non-alphanumeric character
      \d     any Digit
      \D     any Non-digit character
      \s     any Whitespace
      \S     any Non-whitespace character