Can't do regex matching in Swift - regex

Question

I am working on a Swift project and I need to use this regex to check email is valid or not but when the app start the checking the app crash and give me this error:
NSInternalInconsistencyException', reason: 'Can't do regex matching, reason: Can't open pattern U_REGEX_MISSING_CLOSE_BRACKET
This is my REGEX:
^(([^<>()[\\]\\.,;:\\s#\\\"]+(\\.[^<>()[\\]\\.,;:\\s#\\\"]+)*)|(\\\".+\\\"))#((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\])|(([a-zA-Z\\-0-9]+[\\.]*)+[a-zA-Z]{2,}))$

Answer 1

Check unescaped brackets in your regex pattern:
let pattern
= "^(([^<>()[\\]\\.,;:\\s#\\\"]+(\\.[^<>()[\\]\\.,;:\\s#\\\"]+)*)|(\\\".+\\\"))"
// [ [ ] [ [ ]
+ "#((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\])|(([a-zA-Z\\-0-9]+[\\.]*)+[a-zA-Z]{2,}))$"
// [ ] [ ] [ ] [ ] [ ] [ ] [ ]
You have some mismatching brackets [ ] in the first half of your pattern.
In some dialects of regex, you have no need to escape [ between [ and ], but in some other dialects, you need it.
Try adding some escapes to your regex:
let pattern
= "^(([^<>()\\[\\]\\.,;:\\s#\\\"]+(\\.[^<>()\\[\\]\\.,;:\\s#\\\"]+)*)|(\\\".+\\\"))"
// [ ^^ ] [ ^^ ]
+ "#((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\])|(([a-zA-Z\\-0-9]+[\\.]*)+[a-zA-Z]{2,}))$"
// [ ] [ ] [ ] [ ] [ ] [ ] [ ]