If you’re doing voice with Teams or Skype for Business, chances are good that you need to do regex. While some regex’s can get awfully complex, there are some basic ones that look like they should be easy, but are deceptively complex. If you’re writing your own regex, you should be testing it with at least these values:

• The first number in the range
• One less than the first number in the  range
• The last number in the range
• One more than the last number in the range
• A number somewhere in the middle of the range

Well, that sounds like no fun at all if you have to place 5 test phone calls and check logs to make sure things worked. Sure SfB Server has some testing tools build into the control panel, but what about if you’re working on a Ribbon SBC or Microsoft Phone System?

Enter one of my favourite sites, http://www.regex101.com. Pop in your regular expression, enter your test value in the “test string” field, and if it turns green you’ve matched. On the right, you get a breakdown on the various elements in your regex, what each means, and if these individual bits match, and there’s a quick reference too – a great way to learn regex!

Here’s an example. The regex ^(12\d{2})$ is for the range 1200-1299, and I’m testing that 1299 is a match:

Pretty awesome stuff!