how to replace 'abc' to 'a\0\0c'

Question

how to replace 'abc' to 'a\0\0c'

the following code is fail and give output 'ac'

<?php
 $input = 'abc';
 $pattern = '/b/i';
 $replace = "\\0\\0";
 $output = preg_replace($pattern, $replace, $input);
 echo $output;
?>

Answer 1

Have you tried

$replace = '\\0\\0';

?

Answer 2

When in doubt add more backslashes:

$replace = '\\\\0\\\\0';

The first level of escaping is for the PHP string parser. Both single quotes and double quotes interpret \\ as \. The next level is for the regex parser.

So PHP sees:

\\\\0\\\\0

which it interprets as:

\\0\\0

which the regex parser interprets as the literal string:

\0\0

Answer 3

here's a "neater" another way without those extra slashes

$string="abc";
$s = split("[bB]",$string);
print_r( implode('\0\0' , $s) );