I've got ISBN numbers (10-digits and 13 digits) without the dashes. Now I'm looking for a way to add those dashes automatically.
I found some useful information here: http://www.isbn.org/standards/home/isbn/international/hyphenation-instructions.asp
But I'm not sure if it's doable at all, because the publisher identifier has a random length, and without knowing it, it's maybe not possible to determine the correct positions for the dashes.
Does anybody know if it's possible somehow?
Thanks a lot!
You can deduce the length of the publisher identifier if you have the full range tables.
Example 1. ISBN 0141439564 (Penguin: Great Expectations)
Example 2. ISBN 2253004227 (Poche: Gérminal)
You can check your algorithm at the Library of Congress's ISBN hyphenation tool.