Generate 7 digit number similar to original number in PHP

Question

I would like to generate 7 digit number that is very similar to the original randomized number in PHP.

The purpose is: the original randomized number simulates the telephone number that is used in a sound game where users identifies the correct number while listening to the audio.

Using loop

$original_randomized_number=rand(1000000,9999999);
for ($x = 1; $x <= 3; $x++) {
$generated_telephones[$x] = rand(1000000,9999999);
}

to generate 3 random telephone numbers works, but it is too simple to identify the correct number.

Fe the original randomized number 9876543 - the desired result similar to - 9865742, 8896558, 9586543

Answer 1

https://www.tehplayground.com/WJiQXDOWT5CR5SwS

$phone = "9876543";
function getSimilar($phone, $num) {
    $out = array();
    for( $x=0; $x<$num; $x++) {
    $new = array();
    $p = str_split($phone);
    $ctr=2;
    foreach ($p as $n) {
     $neg = rand(0,10) > 5? 1:-1;
     $n = abs((intVal($n) + ( rand(0,$ctr) * $neg)) );
     $new[] = min($n,9);
     $ctr++;
    }
    $out[]=implode("",$new); 
  }

  return $out;

}

$nphone = getSimilar($phone, 5);
echo $phone . "\n";
print_r( $nphone);

example output:

Array
(
    [0] => 9634999
    [1] => 7988194
    [2] => 9896724
    [3] => 8949969
    [4] => 8998434
)