Regular Expression - 4 digits in a row, but can't be all zeros

Question

I am looking for a solution that can exclusively be done with a regular expression. I know this would be easy with variables, substrings, etc.

And I am looking fo

Answer 1

Test for a sequence of 3 digits (0-9), then a 4th with only (1-9)

/\d{3}[1-9]/