How to extract email addresses from a string in PHP?

In this article, we will discuss how to extract an email address from a given string in PHP. First of all, we have to understand what is a valid email address.

See also,

• Email validation in PHP using FILTER_VALIDATE_EMAIL

Basic rules for a valid email address

The following rules are for a valid email,

1. Email addresses use only alphanumeric characters like- A-Z, a-z, 0-9, etc.
2. Special characters like- ^ $ ! < > [ ] ,etc. are not allowed.
3. Must have @ symbol.
4. Except for the first character, hyphens ( – ), underscores ( _ ), periods ( . ) can be used within the address.

How to fetch email addresses from a given string in PHP

In PHP,  email addresses can only be verified using methods like-preg_match(), preg_match_all() etc.

Let us write the script for retrieving email addresses,

<?php

//String to be checked for email addresses
 $tstr = '
My first e-mail address is [email protected]
My second e-mail address is [email protected]
Obviously, this is not an email address: [email protected]^gmail.co.in
';
 
//test string for checking email
$test_patt ="/(?:[a-z0-9!#$%&'*+=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+=?^_`{|}~-]+)*|\"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*\")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])/";

//comapare using preg_match_all() method 
preg_match_all($test_patt, $tstr, $valid);
 
//display list of emails
foreach($valid[0] as $mail){
  echo $mail."<br> ";
}
?>

Output:-

[email protected]
[email protected]

Let us shorten the pattern string and rewrite the script using the function,

<?php
function fetch_mails($text){
    
  //String that recognizes an e-mail
    $str = '/([a-z0-9_\.\-])+\@(([a-z0-9\-])+\.)+([a-z0-9]{2,4})+/i';
    preg_match_all($str, $text, $out);
  //return a blank array if not true otherwise insert the email in $out and return
    return isset($out[0]) ? $out[0] : array();
}
//string to be checked
$tstr = '
My first e-mail address is [email protected]
My second e-mail address is [email protected]
Obviously this is not a emaail address: [email protected]^gmail.co.in
';
//display email addresses
echo"<pre>";
print_r(fetch_mails($tstr));
?>

Output:-

Array
(
    [0] => [email protected]
    [1] => [email protected]
)

Let us rewrite the script without using the function that returns only unique email addresses,

Fetch email address from a string in PHP with this below program.

<?php

  //String to be checked for emails
    $tstr = '
My first e-mail address is [email protected]
My second e-mail address is [email protected]
Obviously, this is not an email address: [email protected]^gmail.co.in
My last e-mail address is again [email protected]
';

    //generate an empty array.
    $match = array();

    //String that recognize a e-mail
    $test_pat = '/[A-Za-z0-9._%+-][email protected][A-Za-z0-9.-]+\.[A-Za-z]{2,4}/';

    //check testpattern in given string
    preg_match_all($test_pat, $tstr, $match);
  echo"<pre>";
    //seleccting only the unique ones
    var_dump(array_values(array_unique($match[0])));
  echo"</pre>";
    //store above in array for upcoming bit.
    $newArr = array_values(array_unique($match[0]));

    //count no. of emails
    $count_Arr = count($newArr);

    //converting to one string
    $mail_str = implode("<br>", $newArr);

    //display the values
    echo "<h3>Fetched uniqe $count_Arr email address are:</h3> $mail_str";

?>

Output:-

array(2) {
  [0]=>
  string(20) "[email protected]"
  [1]=>
  string(25) "[email protected]"
}
Fetched unique 2 email address are:
[email protected]
[email protected]

This is how we can retrieve email addresses from a given string in PHP. If you have any doubt, put a comment.