Check if a string contains at least a upperCase letter, a digit, or a special character in Swift?

Question

I am trying to create a method that finds whether a string contains a number , Upper case letter and a special character using regular expression as below

 func         


        

Answer 1

Another alternate solution.

You can do all the check using one regular expression.

RegExp: ^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)(?=.*[$@$!%*?&])[A-Za-z\\d$@$!%*?&]{8,}

You can use this as mention below:

//Minimum 8 characters at least 1 Uppercase Alphabet, 1 Lowercase Alphabet, 1 Number and 1 Special Character:
let regex = "^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)(?=.*[$@$!%*?&])[A-Za-z\\d$@$!%*?&]{8,}"
let isMatched = NSPredicate(format:"SELF MATCHES %@", regex).evaluate(with: yourTextField.text)
if(isMatched  == true) {
    // Do your stuff ..
}  else {
    // Show Error Message.
}

Answer 2

At least 1 Uppercase, 1 Lowercase, 1 Special Characters, 1 Number, and Total 8 Characters.

To support all special characters listed in https://www.owasp.org/index.php/Password_special_characters

!"#$%&'()*+,-./:;<=>?@[]^_`{|}~

extension String {
    func isValidPassword() -> Bool {
        //let passwordRegex = "^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)(?=.*[ !\"\\\\#$%&'()*+,-./:;<=>?@\\[\\]^_`{|}~])[A-Za-z\\d !\"\\\\#$%&'()*+,-./:;<=>?@\\[\\]^_`{|}~]{8,}"
        //safe to escape all regex chars
        let passwordRegex = "^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)(?=.*[ !\"\\\\#$%&'\\(\\)\\*+,\\-\\./:;<=>?@\\[\\]^_`\\{|\\}~])[A-Za-z\\d !\"\\\\#$%&'\\(\\)\\*+,\\-\\./:;<=>?@\\[\\]^_`\\{|\\}~]{8,}"
        return NSPredicate(format: "SELF MATCHES %@", passwordRegex).evaluate(with: self)
    }
}

Answer 3

Simply replace your RegEx rule [A-Z]+ with .*[A-Z]+.* (and other RegEx rules as well)

Rules

[A-Z]+ matches only strings with all characters capitalized

Examples: AVATAR, AVA, TAR, AAAAAA
Won't work: AVATAr

.* matches all strings (0+ characters)

Examples: 1, 2, AVATAR, AVA, TAR, a, b, c

.*[A-Z]+.* matches all strings with at least one capital letter

Examples: Avatar, avataR, aVatar

Explanation:

I. .* will try to match 0 or more of anything
II. [A-Z]+ will require at least one capital letter (because of the +)
III. .* will try to match 0 or more of anything

Avatar [empty | "A" | "vatar"]
aVatar ["a" | "V" | "atar"]
aVAtar ["a" | "VA" | "tar"]

Working Code

func checkTextSufficientComplexity(var text : String) -> Bool{


    let capitalLetterRegEx  = ".*[A-Z]+.*"
    var texttest = NSPredicate(format:"SELF MATCHES %@", capitalLetterRegEx)
    var capitalresult = texttest!.evaluateWithObject(text)
    println("\(capitalresult)")


    let numberRegEx  = ".*[0-9]+.*"
    var texttest1 = NSPredicate(format:"SELF MATCHES %@", numberRegEx)
    var numberresult = texttest1!.evaluateWithObject(text)
    println("\(numberresult)")


    let specialCharacterRegEx  = ".*[!&^%$#@()/]+.*"
    var texttest2 = NSPredicate(format:"SELF MATCHES %@", specialCharacterRegEx)

    var specialresult = texttest2!.evaluateWithObject(text)
    println("\(specialresult)")

    return capitalresult || numberresult || specialresult

}

Examples:

checkTextSufficientComplexity("Avatar") // true || false || false
checkTextSufficientComplexity("avatar") // false || false || false
checkTextSufficientComplexity("avatar1") // false || true || false
checkTextSufficientComplexity("avatar!") // false || false || true

Answer 4

Here is a concise version of Joshuas answer in Swift 3, assuming that all validations must be fulfilled.

func validate(password: String) -> Bool {
    let capitalLetterRegEx  = ".*[A-Z]+.*"
    let texttest = NSPredicate(format:"SELF MATCHES %@", capitalLetterRegEx)
    guard texttest.evaluate(with: password) else { return false }

    let numberRegEx  = ".*[0-9]+.*"
    let texttest1 = NSPredicate(format:"SELF MATCHES %@", numberRegEx)
    guard texttest1.evaluate(with: password) else { return false }

    let specialCharacterRegEx  = ".*[!&^%$#@()/_*+-]+.*"
    let texttest2 = NSPredicate(format:"SELF MATCHES %@", specialCharacterRegEx)
    guard texttest2.evaluate(with: password) else { return false }

    return true
}