Regex for 2 numbers of the same length separated by dash

Question

What's the right regex for matching the following criteria:

• Two numbers, separated by a dash (-)
• Both numbers must have the same amount of digits, but at least 1 and not more than 5 digits
• before/after/between numbers and the dash there may be arbitrary whitespace

Examples that match:

• 123-444
• 1234 - 5678
• 98- 76

Examples that shouldn't match:

• 1234-567
• 123456-789012

Is such a thing possible?

Answer 1

Probably you can use this:

^ *((\d *- *\d)|(\d{2} *- *\d{2})|(\d{3} *- *\d{3})|(\d{4} *- *\d{4})|(\d{5} *- *\d{5})) *$

Online Demo: http://regex101.com/r/jG0dB7