I have written this function in String Extension and can't figure out the error.
func isEmail() -> Bool {
let regex = NSRegularExpression(pattern: "^[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,4}$", options: [.CaseInsensitive])
return regex.firstMatchInString(self, options: nil, range: NSMakeRange(0, characters.count)) != nil
}
The error is:
Call can throw, but it is not marked with 'try' and the error is not handled
That's because that initializer can now throw an exception, so you need to try
to call it and be prepared to catch
the exception. You can do this by adding try
before the initializer and annotating your method with throws
.
extension String {
func isEmail() throws -> Bool {
let regex = try NSRegularExpression(pattern: "^[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,4}$", options: [.CaseInsensitive])
return regex.firstMatchInString(self, options: NSMatchingOptions(rawValue: 0), range: NSMakeRange(0, characters.count)) != nil
}
}
Then when you want to call the method, do it from within a do
block and catch the error that comes out.
do {
try "[email protected]".isEmail()
} catch {
print(error)
}
Note: I've also updated your regex.firstMatchInString
call to reflect the fact that the options
parameter can no longer take a nil value.
NSRegularExpression(pattern:)
throws an error if the pattern is invalid. In your case, the pattern is fixed, so an invalid pattern
would be a programming error.
This is a use-case for the "forced-try" expression with try!
:
extension String {
func isEmail() -> Bool {
let regex = try! NSRegularExpression(pattern: "^[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,4}$",
options: [.CaseInsensitive])
return regex.firstMatchInString(self, options:[],
range: NSMakeRange(0, utf16.count)) != nil
}
}
try!
disables the error propagation so that the method does not
throw an error (which the caller has to catch). It will abort with a
runtime exception if the pattern is invalid, which helps to find
programming errors early.
Note also that NSRange()
counts the length of NSString
, i.e. the number of UTF-16 code points, so
characters.count
should be utf16.count
, otherwise it might crash
e.g. with Emoji characters.
If you don't like try catch :
extension String {
func matchPattern(patStr:String)->Bool {
var isMatch:Bool = false
do {
let regex = try NSRegularExpression(pattern: patStr, options: [.CaseInsensitive])
let result = regex.firstMatchInString(self, options: NSMatchingOptions(rawValue: 0), range: NSMakeRange(0, characters.count))
if (result != nil)
{
isMatch = true
}
}
catch {
isMatch = false
}
return isMatch
}
}
check string is correct email format :
let emailInput:String = "[email protected]"
if (emailInput.matchPattern("^[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,4}$"))
{
print("this is e-mail!")
}
You could use string.rangeOfString, and specify the option to .RegularExpressionSearch. It's simple.
func isEmail(email: String) -> Bool {
return email.rangeOfString("^[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,6}$", options: .RegularExpressionSearch) != nil
}
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