regex pattern to validate email

To validate an email using a regular expression (regex) pattern in Kotlin, you can use the following pattern:

val pattern = Regex("^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}\$")

Let's break down the regex pattern and explain each step:

^

• The caret symbol ^ indicates the start of the line.

[A-Za-z0-9._%+-]+

• This part matches one or more occurrences of characters that can be letters (both uppercase and lowercase), digits, or any of the following special characters: ._%+-.

@

• This matches the literal @ symbol.

[A-Za-z0-9.-]+

• This part matches one or more occurrences of characters that can be letters (both uppercase and lowercase), digits, or any of the following special characters: .-.

\\.

• This matches the literal . symbol. Since . is a special character in regex, we need to escape it with a backslash \.

[A-Za-z]{2,}

• This part matches two or more occurrences of characters that can be letters (both uppercase and lowercase).

\

• The backslash \ is used to escape the dollar sign $, which is a special character in regex.

$

• The dollar sign $ indicates the end of the line.

So, in summary, the regex pattern ^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}$ validates an email address by checking if it starts with one or more occurrences of letters, digits, and certain special characters, followed by an @ symbol, followed by one or more occurrences of letters, digits, and certain special characters, followed by a dot . symbol, and ends with two or more occurrences of letters. This pattern ensures that the email address follows a common format.

To use this regex pattern in Kotlin, you can create a Regex object like this:

val pattern = Regex("^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}\$")

You can then use this pattern to validate an email address by calling the matches function on the pattern and passing in the email address as a string:

val email = "[email protected]"
val isValidEmail = pattern.matches(email)

The isValidEmail variable will be true if the email address is valid according to the regex pattern, and false otherwise.