Question

I found here many responses for my question but I cat’t find exactly what I am looking for.
I have to remove every 4th digit from an array, but beginning and the end making a circle, so If I remove 4th digit in next loop It’s gonna be another digit (maybe 4th maybe 3rd) It’s depend how many digit we have in string

$string = "456345673474562653265326";
$chars = preg_split('//', $string, -1, PREG_SPLIT_NO_EMPTY);
$result = array();
for ($i = 0; $i < $size; $i += 4) 
{
    $result[] = $chars[$i];
}

Answer 1

<?php
$string = "abcdef";
$chars = str_split($string);

$i = 0;
while (count($chars) > 1) {
    $i += 3;
    $n = count($chars);
    if ($i >= $n)
        $i %= $n;

    unset($chars[$i]);
    $chars = array_values($chars);

    echo "DEBUG LOG: n: $n, i: $i; s: " . implode($chars, '') . "\n";
}
?>

Output:

DEBUG LOG: n: 6, i: 3; s: abcef
DEBUG LOG: n: 5, i: 1; s: acef
DEBUG LOG: n: 4, i: 0; s: cef
DEBUG LOG: n: 3, i: 0; s: ef
DEBUG LOG: n: 2, i: 1; s: e