This post was published more than a few years ago (on 2014-06-01) and may contain inaccurate technical information, outmoded thoughts, or cringe takes. Proceed at your own risk.
I'm building a website, and needed a way to save a list of pages and page ranges from a book or magazine. I wanted to to be a little more strict than just saving it as a string without any cleanup or validation, so I wrote a custom Django model field (and accompanying form field).
It either just validates and cleans so that
4-33, 43, 45, 60-65, 44, 59
becomes the tidy
4-33, 43-45, 59-65
...or, if you comment out the raising of the ValidationError in the form field's validate() method, it will actually clean up any junk characters for you, so even this horrible mess:
;4-33, 46a fads i44 ,p45o
gets cleaned to
4-33, 44-46