Replacing last x amount of numbers - php

Question

I have a PHP variable that looks a bit like this:
$id = "01922312";
I need to replace the last two or three numbers with another character. How can I go about doing this?
EDIT Sorry for the confusion, basically I have the variable above, and after I'm done processing it I'd like for it to look something like this:
$new = "01922xxx";

Answer 1

Try this:
$new = substr($id, 0, -3) . 'xxx';
Result:
01922xxx

Answer 2

You can use substr_replace to replace a substring.
$id = substr_replace($id, 'xxx', -3);
Reference:
http://php.net/substr-replace

Answer 3

function replaceCharsInNumber($num, $chars) {
return substr((string) $num, 0, -strlen($chars)) . $chars;
}
Usage:
$number = 5069695;
echo replaceCharsInNumber($number, 'xxx'); //5069xxx
See it in action here: http://codepad.org/XGyVQ1hk

Answer 4

Strings can be treated as arrays, with the characters being the keys:
$id = 1922312; // PHP converts 01922312 => 1 because of that leading zero. Either make it a string or remove the zero.
$id_str = strval($id);
for ($i = 0; $i < count($id_str); $i++)
{
print($id_str[$i]);
}
This should output your original number. Now to do stuff with it, treat it as a normal array:
$id_str[count($id_str) - 1] = 'x';
$id_str[count($id_str) - 2] = 'y';
$id_str[count($id_str) - 3] = 'z';
Hope this helps!

Answer 5

Just convert to string and replace...
$stringId = $id . '';
$stringId = substr($id, 0, -2) . 'XX';

Answer 6

We can replace specific characters in a string using preg_replace(). In my case, I want to replace 30 with 50 (keep the first two digits xx30), in the $start_time which is '1030'.
Solution:
$start_time = '1030';
$pattern = '/(?<=\d\d)30/';
$start_time = preg_replace($pattern, '50', $start_time);
//result: 1050