Pattern matching email address using regular expressions [duplicate]

This question already has answers here: How can I validate an email address using a regular expression? (79 answers) Closed 2 years ago.

Filter email address with regular expressions: I am new to regular expressions and was hoping someone might be able to help out.

I am trying to pattern match an email address string with the following format:

FirstName.LastName@gmail.com

I want to be sure that there is a period somewhere before the '@' character and that the characters after the '@开发者_如何转开发' character matches gmail.com

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You want some symbols before and after the dot, so I would suggest .+\..+@gmail\.com.

.+ means any symbols (.) can appear 1 or more times (+)
\. means the dot symbol; screened with backslash to suppress the special meaning of .
@gmail and com should be matched exactly.

See also Regular Expression Basic Syntax Reference

EDIT: gmail rules for account name only allow latin letters, digits, and dots, so a better regex is
[a-zA-Z0-9]+\.[a-zA-Z0-9]+@gmail\.com

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check valid email

^(?:(?!.*?[.]{2})[a-zA-Z0-9](?:[a-zA-Z0-9.+!%-]{1,64}|)|\"[a-zA-Z0-9.+!% -]{1,64}\")@[a-zA-Z0-9][a-zA-Z0-9.-]+(.[a-z]{2,}|.[0-9]{1,})$

enforced rules:

• must start with alphanumeric char
• can only have alphanumeric and @._-% char
• cannot have 2 consecutives . exept for quoted string
• char before @ can only be alphanumeric and ._-%, exept for quoted string
• must have @ in the middle
• need to have at least 1 . in the domain part
• cannot have double - in the domain part
• can only have alphanumeric and .- char in the domain part
• need to finish by a valid extension of 2 or more letters
• support IP address (test@1.1.1.1)
• support for quoted user name

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You don't even need regex since your requirements are pretty specific. Not sure what language you're using, but most would support doing a split on @ and checking for a .. In python:

name, _, domain = email.partition('@')
if '.' in name and domain == 'gmail.com':
    # valid

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You haven't tell us what kind of regex flavor you need however this example will fit most of them:

.*\..*@gmail.com

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Assuming Unix style where . is any character: .*\..*@gmail\.com

Edit: escaped the . in the domain

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I used follwing regex expression to validate the email address. Also I have added a small code snippet in C# language regarding to that.

Regex - "^[a-zA-Z0-9]{3,20}@gmail.com$"

Code :-

static void Main(string[] args)
        {
            Console.WriteLine("Enter Your Text ");
            string input = Console.ReadLine();
            Console.WriteLine("The Text that you have entered is :" + input);
            Console.ReadLine();

            string pattern = "^[a-zA-Z0-9]{3,20}@gmail.com$";
            Regex regex = new Regex(pattern);
            bool results = regex.IsMatch(input);
            Console.WriteLine(results.ToString());
            Console.ReadLine();
        }

Emails such as ∂øøµ$∂å¥!@gmail.com also checked and show as false here. ;-)