Verify a string as a valid UUID in Swift

Question

Given an supplied String, how can I verify wether the String is a valid UUID in Swift?

A valid UUID (as far as I know) could be:

33041937-05b2-464a-98ad-3910cbe0d09e 3304193705b2464a98ad3910cbe0d09e 

Answer 1

You could use UUID

var uuid = UUID(uuidString: yourString) 

This will return nil if yourString is not a valid UUID

Note: this only validates the first case you presented, not the second but adding the dashes yourself is trivial.

Answer 2

The following is updated for Swift 4.0 to determine if a string is a valid UUID.

let uuidHyphens = "33041937-05b2-464a-98ad-3910cbe0d09e" let uuidNoHyphens = "3304193705b2464a98ad3910cbe0d09e"  if UUID(uuidString: uuidHyphens) != nil {     print("UUID string with hypens is valid") // Will be valid } else {     print("UUID string with hypens is not valid") }  // In this scenario, the UUID will be nil, if UUID(uuidString: uuidNoHyphens) != nil {     print("UUID string with no hypens is valid") } else {     print("UUID string with no hypens is not valid") // Will not be valid } 

The string passed in to the UUID init must contain hyphens, otherwise the check will fail. If you are expecting strings without hypens, then you can utilize an approach such as what is discussed here to add hypens to a string if it satisfies a length of 32.

The relevant section from Apple's documentation:

Create a UUID from a string such as “E621E1F8-C36C-495A-93FC-0C247A3E6E5F”.