Searching for UUIDs in text with regex

Question

I'm searching for UUIDs in blocks of text using a regex. Currently I'm relying on the assuming that all UUIDs will follow a patttern of 8-4-4-4-12 hexadecimal digits.

Can anyone think of a use case where this assumption would be invalid and would cause me to miss some UUIDs?

Answer 1

By definition, a UUID is 32 hexadecimal digits, separated in 5 groups by hyphens, just as you have described. You shouldn't miss any with your regular expression.

http://en.wikipedia.org/wiki/Uuid#Definition

Answer 2

I agree that by definition your regex does not miss any UUID. However it may be useful to note that if you are searching especially for Microsoft's Globally Unique Identifiers (GUIDs), there are five equivalent string representations for a GUID:

"ca761232ed4211cebacd00aa0057b223" 

"CA761232-ED42-11CE-BACD-00AA0057B223" 

"{CA761232-ED42-11CE-BACD-00AA0057B223}" 

"(CA761232-ED42-11CE-BACD-00AA0057B223)" 

"{0xCA761232, 0xED42, 0x11CE, {0xBA, 0xCD, 0x00, 0xAA, 0x00, 0x57, 0xB2, 0x23}}"

Answer 3

[\w]{8}(-[\w]{4}){3}-[\w]{12} has worked for me in most cases

Or if you want to be really specific [\w]{8}-[\w]{4}-[\w]{4}-[\w]{4}-[\w]{12}