Regular expression for validating numbers
Let's look at a simple break-down of this expression : ^ # Beginning of expression \d # Exactly three digits (denoted by \d and the specifies the number) - # An explicit 'dash' \d # Exactly two digits - # Another explicit 'dash' \d # Exactly four digits $ # End of expression This doesn't take into consideration any of the previously suggested rules and exceptions that were mentioned above, but it does function to ensure that the number is in the proper format.
You can see an example of this in action below : While this may not look very fun at all, it will validate any valid Social Security Number as per the constraints (and exceptions) listed by the Social Security Administration.
Searching for var names is totally legit, and totally works — the results, however, will not resolve down to the assigned value.
On the flip side, however, you can assign a regular expression to a variable, and even use the return value as a test condition: Exact searches, and Boolean returns, are both useful and ultimately limited.
Let’s break this one down : ^ # Start of expression (?!
Java supports regular expression using for regular expression in Java.
Java supports regex from JDK 1.4, means well before Generics, Enum or Autoboxing.
Use your best judgement to determine if this is a viable option for you and your business needs.
You can see this expression in action below : If you truly need a reliable method of handling Social Security Number validation, the Social Security Administration offers a service that will properly validate a number for you, however it may not always be free or very quick.