How To Parse String in format "Name <Email>"

Question

I have a method which receives a contact in one of the following formats:

1 - "email@domain.com"

2 - "Name <email@domain.com>" OR "Name<email@domain.com>" (Spaces can exist)

If it is in format (1) I do nothing. In case of (2) I need to parse the name and email.

I never know in which format I will get the emails. But it will be one of the two.

How can I do this?

Answer 1

There is actually already a .NET class called MailAddress that can do this for you quite simply.
UPDATE: It can not only get the display name but also the email address, username, and host.

First include using System.Net.Mail and then you can get the info with something like this:

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MailAddress email = new MailAddress("Johnny <johnny@example.com>");
string displayName = email.DisplayName;
string address = email.Address;
string user = email.User;
string host = email.Host;

This will work with the two scenarios that you described so "Name <email@domain.com>" and "Name<email@domain.com>" both work and give you Name. I went on and created a test that can be found here that will give you the sample output of:

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'email@domain.com' =
   DisplayName = ''
   Address = 'email@domain.com'
   User = 'email'
   Host = 'domain.com'
'Name<email@domain.com>' =
   DisplayName = 'Name'
   Address = 'email@domain.com'
   User = 'email'
   Host = 'domain.com'
'Name <email@domain.com>' =
   DisplayName = 'Name'
   Address = 'email@domain.com'
   User = 'email'
   Host = 'domain.com'

Answer 2

MailAddress is a great solution, but unfortunately System.Net.Mail has not yet been ported to .NET Core.

I find that the following Regex solution works for reasonably well-formed inputs:

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var re = new Regex(@"""?((?<name>.*?)""?\s*<)?(?<email>[^>]*)");
var match = re.match(input);

var name = match.Groups["name"].Value;
var email = match.Groups["email"].Value;

I have tested this with the following kinds of inputs:

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bob@example.com
<bob@example.com>
Bob Example <bob@example.com>
Bob Example<bob@example.com>
"Bob Example" <bob@example.com>
"Example, Bob J." <bob@example.com>