RegexdrillUUIDs
A regex exercise from Regexdrill. Solve it with a pattern box with live highlighting in your browser, checked against hidden test strings, and it is checked the moment you submit.
The task
The whole line must match. Match a lowercase UUID: five groups of hex digits (0 to 9 and a to f) with lengths 8, 4, 4, 4 and 12, separated by hyphens.
What this exercise teaches
[0-9a-f]{8}(?:-[0-9a-f]{4}){3}-[0-9a-f]{12} fixes every group length and hyphen position. A single class with the hyphen in it, repeated 36 times, would accept hyphens anywhere.
A hint if you get stuck
Spell the group lengths out with counted repeats. The three middle groups have the same shape, so a counted group can cover them.
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