How to validate an email address in Swift

This tutorial will see how to validate an email address in Swift. This is possible by taking an email address as a string and checking it with the regular expression of valid emails. Regular expression allows us to run a complex search and replace operations on a large number of combinations.

Step 1: Import the foundation library which contains all the basic functions, classes, and data types of swift.

Step 2: Declare the isvalid named function to check whether an email is valid or not of a return type string and pass an email (string) as a parameter to the function.

Step 3: Declare the regular expression pattern for email format.

Step 4: Then create an NSRegularExpression instance and pass the previously defined pattern to the instance as a parameter.

Step 5: Then define the NSRange instance with the length as the length of the email string and location as starting index of the string.

Step 6: Finally call the matches function on the regex defined before. Pass the email string to search within and set the range equal to the range defined before.

Step 7: Now if the count of results s equal to zero then return the string as “invalid email” and “valid email” otherwise.

Step 8: call the isvalid function, pass the email string as a parameter, and print the result.

Code: Email validation in Swift

Here is the complete swift code for checking whether the email is valid.

import Foundation
func isValid(email: String) -> String 
{
    
    var returnValue = "Valid Email"
    let emailRegEx = "[A-Z0-9a-z.-_]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,3}"
    let regex = try! NSRegularExpression(pattern: emailRegEx)
    let nsRange = NSRange(location: 0, length: email.length)
    let results = regex.matches(in: email, range: nsRange)
    if results.count == 0
    {
        returnValue = "Invalid Email"
    }
    return  returnValue
}

let Result1 = isValid(email: "donjoe@gmail.com")
print(Result1)
 
let Result2 = isValid(email: "donjoe#email.c")
print(Result2)

Output:

$swift main.swift
Valid Email
Invalid Email

Also, refer to Ways to compare two strings in Swift