How to find the second-to-last occurrence of a character within a string?

Question

If possible, using only standard PHP functions like substr(), strrpos(), strpos(), etc.

Answer 1

I would store all occurrence positions in an array by using the method "explode", and then get the second to last array position, and output the position or do what you need with it.

Answer 2

First, find the last position:

$last = strrpos($haystack, $needle);
if ($last === false) {
  return false;
}

From there, find the 2nd last:

$next_to_last = strrpos($haystack, $needle, $last - strlen($haystack) - 1);

Answer 3

General solution for any number of backwards steps:

function strrpos_count($haystack, $needle, $count)
{
    if($count <= 0)
        return false;

    $len = strlen($haystack);
    $pos = $len;

    for($i = 0; $i < $count && $pos; $i++)
        $pos = strrpos($haystack, $needle, $pos - $len - 1);

    return $pos;
}

Answer 4

With strpos:

$pos = -1; $last = null; $secondLast = null;
while (($pos = strpos($haystack, $needle, $pos+1)) !== false) {
    $secondLast = $last;
    $last = $pos;
}
if (!is_null($secondLast)) {
    echo 'second last occured on '.$secondLast;
}

Answer 5

Search for a regexp (plz correct me if I'm wrong, and how to write it in PHP):

    r'x[^x]*x[^x]*$'.replace('x',your_char)