Question

I feel like I am chasing my tail.

I am trying to arrive at a .Net regex that will match on the following:

mm-dd-yy
m-dd-yy
mm-d-yy
m-d-yy

and (no dashes)

yyyymmdd

Answer 1

One or two digits followed by a dash, followed by one or two digits, followed by a dash, follows by to digits or eight digits:

(\d{1,2}-\d{1,2}-\d{2})|(\d{8})