Replace all characters with * except for specified characters

Question

I need to censor email addresses when a certain page is viewed so that the first letter is visible and the @ sign is visible, but the rest is censored using a * like the example below:

v********@*********

How would I go about doing this? I can't find any answers to this (or maybe I'm just not googling the right thing).

This seems a little specific to find a ready to use script on Google. How would you do it if you wrote the script yourself? — Halcyon, Jun 01 '17 at 09:38
with the loop method the link would be helpful https://stackoverflow.com/questions/8163746/how-to-replace-certain-parts-of-my-string — K.M, Jun 01 '17 at 09:39
Well keeping the first character is easy using substr() but I don't know what regex I'd need to do the rest. An email address could have letters and numbers, but any regex I find doesn't prevent the @ symbol from being replaced. — VenomRush, Jun 01 '17 at 09:41
If you want a regex you can use `/[^@]/` in a replace which matches anything but the `@`. — Jenne, Jun 01 '17 at 09:45
maybe [this](http://php.net/manual/en/function.preg-replace.php) is what you need — hungrykoala, Jun 01 '17 at 09:45

Ethan · Accepted Answer · 2017-06-01T09:54:14.950

4

Short and sweet one liner:

$result = substr($str, 0, 1) . preg_replace('/[^@]/', '*', substr($str, 1));

substr($str, 0, 1) gets the first character of the string e.g. v.
preg_replace('/[^@]/', '*', substr($str, 1)) replaces everything from the first character onwards that isn't an @ symbol.

eval.in demo.

edited Jun 01 '17 at 09:54

answered Jun 01 '17 at 09:48

Ethan

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This worked exactly how I wanted it to. I did the same thing as soon as I saw Jenne van der Meer's comment on my post. – VenomRush Jun 01 '17 at 09:59
@David You are absolutely right, I do apologize. My fault. – arkascha Jun 01 '17 at 09:59

score 0 · Answer 2 · answered Jun 01 '17 at 09:46

<?php

$email = "vmail@vmail.com";

// Split into name and domain
$pieces = explode("@", $email);

// Add the first letter
$censored = substr($email, 0, 1);

// Add the name stars
for ($i = 1; $i <= strlen($pieces[0]) - 1; $i++) {
    $censored = $censored."*";
}

// Add the @ sign
$censored = $censored."@";

// Add the domain stars
for ($i = 1; $i <= strlen($pieces[1]); $i++) {
    $censored = $censored."*";
}

echo $censored;

score 0 · Answer 3 · answered Jun 01 '17 at 09:49

With regex and str_pad?
Use regex to capture the first letter, then the rest in pieces.
Use str_pad to add the "*" in the string.

https://3v4l.org/dvYpT

$mail = "Test@test.com";

preg_match("/(.)(.*?)@(.*)/", $mail, $Match);

$str = $Match[1] . str_pad("", strlen($Match[2]), "*"). "@" . str_pad("", strlen($Match[3]), "*");
echo $str;

score 0 · Answer 4 · answered Jun 01 '17 at 09:57

Use a callback reassembling the string:

<?php
$subject = 'someone@example.com';
$subject = preg_replace_callback('/^(.)(.*)@(.*)$/', function($m) {
  return sprintf(
    '%s%s@%s',
    $m[1],
    str_pad('', strlen($m[2]), '*'),
    str_pad('', strlen($m[3]), '*')
  );
}, $subject);
var_dump($subject);

The output obviously is:

string(19) "s******@***********"

Replace all characters with * except for specified characters

4 Answers4